* avr/z80.asm:

[avrcpm.git] / avrcpm / avr / z80.asm

diff --git a/avrcpm/avr/z80.asm b/avrcpm/avr/z80.asm
index 3d5f0b84ec16455375eaf9f5c2a1e9080f398b07..3aca6452d3ce3f0856c3e596b361f3f54330c38f 100644 (file)
--- a/avrcpm/avr/z80.asm
+++ b/avrcpm/avr/z80.asm
@@ -15,6 +15,9 @@
 ;
 ;    You should have received a copy of the GNU General Public License
 ;    along with this program.  If not, see <http://www.gnu.org/licenses/>.
 ;
 ;    You should have received a copy of the GNU General Public License
 ;    along with this program.  If not, see <http://www.gnu.org/licenses/>.

+;
+;    $Id$
+;

 
 ;.nolist
 #if defined atmega8
 
 ;.nolist
 #if defined atmega8


@@ -40,12 +43,15 @@
        #define BAUD   38400           /* console baud rate */
 #endif
  
        #define BAUD   38400           /* console baud rate */
 #endif
  

+#define PARTID 0x52            /* Partition table id */
+                               /* http://www.win.tue.nl/~aeb/partitions/partition_types-1.html */

 
 #define UBRR_VAL  ((F_CPU+BAUD*8)/(BAUD*16)-1)  /* clever rounding */
 
 #define        RXBUFSIZE 64            /* USART recieve buffer size. Must be power of 2 */
 #define        TXBUFSIZE 64            /* USART transmit buffer size. Must be power of 2 */
 
 
 #define UBRR_VAL  ((F_CPU+BAUD*8)/(BAUD*16)-1)  /* clever rounding */
 
 #define        RXBUFSIZE 64            /* USART recieve buffer size. Must be power of 2 */
 #define        TXBUFSIZE 64            /* USART transmit buffer size. Must be power of 2 */
 

+#define DRAM_WAITSTATES 1      /* Number of additional clock cycles for dram read access */

 #define REFR_RATE   64000       /* dram refresh rate in cycles/s. */
                                /* Most drams need 1/15.6µs. */
 #define REFR_PRE    8           /* timer prescale factor */
 #define REFR_RATE   64000       /* dram refresh rate in cycles/s. */
                                /* Most drams need 1/15.6µs. */
 #define REFR_PRE    8           /* timer prescale factor */


@@ -53,11 +59,6 @@
 #define REFR_CNT    F_CPU / REFR_RATE / REFR_PRE
 
 
 #define REFR_CNT    F_CPU / REFR_RATE / REFR_PRE
 
 

-#if defined __ATmega8__
-       .equ refr_vect = OC2addr
-#else
-       .equ refr_vect = OC2Aaddr
-#endif

 
 #define DRAM_WORD_ACCESS 0     /* experimental */
 
 
 #define DRAM_WORD_ACCESS 0     /* experimental */
 


@@ -69,6 +70,7 @@
 .equ BOOTWAIT    = 1
 .equ PORT_DEBUG  = 0
 .equ DISK_DEBUG  = 0
 .equ BOOTWAIT    = 1
 .equ PORT_DEBUG  = 0
 .equ DISK_DEBUG  = 0

+.equ HOSTRW_DEBUG= 0

 .equ MEMFILL_CB  = 1
 .equ STACK_DBG   = 0
 .equ PRINT_PC    = 0
 .equ MEMFILL_CB  = 1
 .equ STACK_DBG   = 0
 .equ PRINT_PC    = 0


@@ -136,8 +138,6 @@
 .equ ZFL_C     =       0
 
 ;Register definitions
 .equ ZFL_C     =       0
 
 ;Register definitions

-.undef xl              ;r26
-.undef xh              ;r27

 
 .def   _tmp    = r0    ;  0
 .def   _0      = r1
 
 .def   _tmp    = r0    ;  0
 .def   _0      = r1


@@ -164,8 +164,8 @@
 .def   oph     = r23   ;
 .def   z_pcl   = r24   ;
 .def   z_pch   = r25   ;
 .def   oph     = r23   ;
 .def   z_pcl   = r24   ;
 .def   z_pch   = r25   ;

-.def   adrl    = r26   ;
-.def   adrh    = r27   ;
+; xl           ;r26
+; xh           ;r27

 ; yl           ;r28
 ; yh           ;r29
 ; zl           ;r30    ;
 ; yl           ;r28
 ; yh           ;r29
 ; zl           ;r30    ;


@@ -214,6 +214,7 @@
 .equ   UBRR0H  = UBRRH
 .equ   UBRR0L  = UBRRL
 .equ   OCR2A   = OCR2
 .equ   UBRR0H  = UBRRH
 .equ   UBRR0L  = UBRRL
 .equ   OCR2A   = OCR2

+.equ   OC2Aaddr= OC2addr

 .equ   TCCR2A  = TCCR2
 .equ   TCCR2B  = TCCR2
 .equ   TIMSK1  = TIMSK
 .equ   TCCR2A  = TCCR2
 .equ   TCCR2B  = TCCR2
 .equ   TIMSK1  = TIMSK


@@ -248,10 +249,25 @@
 
 
 
 
 
 

+;----------------------------------------
+; add wait states
+;      dram_wait  number_of_cycles
+
+.macro dram_wait
+.if @0 > 1
+       rjmp    PC+1
+       dram_wait @0 - 2
+.elif @0 > 0
+       nop
+       dram_wait @0 - 1
+.endif
+.endm
+
+

 .cseg
 .org 0
        rjmp start              ; reset vector
 .cseg
 .org 0
        rjmp start              ; reset vector

-.org refr_vect
+.org OC2Aaddr

        rjmp refrint            ; tim2cmpa
 .org OC1Aaddr                  ; Timer/Counter1 Compare Match A
        rjmp sysclockint        ; 1ms system timer
        rjmp refrint            ; tim2cmpa
 .org OC1Aaddr                  ; Timer/Counter1 Compare Match A
        rjmp sysclockint        ; 1ms system timer


@@ -279,6 +295,17 @@ start:
        ldi temp,(1<<WDCE)
        outm8   WDTCSR,temp
 
        ldi temp,(1<<WDCE)
        outm8   WDTCSR,temp
 

+; - Clear RAM
+
+       ldi     zl,low(SRAM_START)
+       ldi     zh,high(SRAM_START)
+       ldi     temp2,high(ramtop)
+clr_l:
+       st      z+,_0
+       cpi     zl,low(ramtop)
+       cpc     zh,temp2
+       brne    clr_l
+

 ; - Setup Ports
        ldi     temp,(1<<PUD)           ;disable pullups
        outm8   P_PUD,temp
 ; - Setup Ports
        ldi     temp,(1<<PUD)           ;disable pullups
        outm8   P_PUD,temp


@@ -298,13 +325,6 @@ start:
 
 ; - Init serial port
 
 
 ; - Init serial port
 

-       sts     rxcount,_0      ; reset receive buffer
-       sts     rxidx_r,_0
-       sts     rxidx_w,_0
-       sts     txcount,_0      ; reset transmit buffer
-       sts     txidx_r,_0
-       sts     txidx_w,_0
-       

        ldi temp, (1<<TXEN0) | (1<<RXEN0) | (1<<RXCIE0)
        outm8 UCSR0B,temp
 .ifdef URSEL
        ldi temp, (1<<TXEN0) | (1<<RXEN0) | (1<<RXCIE0)
        outm8 UCSR0B,temp
 .ifdef URSEL


@@ -318,30 +338,8 @@ start:
        ldi temp, LOW(UBRR_VAL)
        outm8 UBRR0L,temp
 
        ldi temp, LOW(UBRR_VAL)
        outm8 UBRR0L,temp
 

-;Init timer2. Refresh-call should happen every (8ms/512)=312 cycles.
-
-       ldi     temp,REFR_CNT*2                 ; 2 cycles per int
-       outm8   OCR2A,temp
-       inm8    temp,TCCR2A
-       ori     temp,(1<<WGM21)                 ;CTC mode
-       outm8   TCCR2A,temp
-       inm8    temp,TCCR2B
-       ori     temp,REFR_CS                    ;clk/REFR_PRE
-       outm8   TCCR2B,temp
-       inm8    temp,TIMSK2
-       ori     temp, (1<<OCIE2A)
-       outm8   TIMSK2,temp
-

 ; Init clock/timer system
 
 ; Init clock/timer system
 

-       ldi     zl,low(timer_base)
-       ldi     zh,high(timer_base)
-       ldi     temp2,timer_size
-ti_loop:
-       st      z+,_0
-       dec     temp2
-       brne    ti_loop
-

 ; Init timer 1 as 1 ms system clock tick.
 
        ldi     temp,high(F_CPU/1000)
 ; Init timer 1 as 1 ms system clock tick.
 
        ldi     temp,high(F_CPU/1000)


@@ -354,6 +352,20 @@ ti_loop:
        ori     temp,(1<<OCIE1A)
        outm8   TIMSK1,temp
 
        ori     temp,(1<<OCIE1A)
        outm8   TIMSK1,temp
 

+;Init timer2. Refresh-call should happen every (8ms/512)=312 cycles.
+
+       ldi     temp,REFR_CNT*2                 ; 2 cycles per int
+       outm8   OCR2A,temp
+       inm8    temp,TCCR2A
+       ori     temp,(1<<WGM21)                 ;CTC mode
+       outm8   TCCR2A,temp
+       inm8    temp,TCCR2B
+       ori     temp,REFR_CS                    ;clk/REFR_PRE
+       outm8   TCCR2B,temp
+       inm8    temp,TIMSK2
+       ori     temp, (1<<OCIE2A)
+       outm8   TIMSK2,temp
+

        sei
 
 
        sei
 
 


@@ -367,23 +379,18 @@ ti_loop:
        .db "CPM on an AVR, v1.0",13,0,0
 
 
        .db "CPM on an AVR, v1.0",13,0,0
 
 

-       rcall printstr
-       .db "Initing mmc...",13,0
-       rcall mmcInit
-
-

 .if MEMTEST
        rcall printstr
        .db "Testing RAM: fill...",0,0
 
 ;Fill RAM
 .if MEMTEST
        rcall printstr
        .db "Testing RAM: fill...",0,0
 
 ;Fill RAM

-       ldi adrl,0
-       ldi adrh,0
+       ldi xl,0
+       ldi xh,0

 ramtestw:
 ramtestw:

-       mov temp,adrh
-       eor temp,adrl
+       mov temp,xh
+       eor temp,xl

        rcall memwritebyte
        rcall memwritebyte

-       adiw adrl,1
+       adiw xl,1

        brcc ramtestw
        rcall printstr
        .db "wait...",0
        brcc ramtestw
        rcall printstr
        .db "wait...",0


@@ -399,61 +406,170 @@ ramtestwl:
        .db "reread...",13,0,0
 
 ;re-read RAM
        .db "reread...",13,0,0
 
 ;re-read RAM

-       ldi adrl,0
-       ldi adrh,0
+       ldi xl,0
+       ldi xh,0

 ramtestr:
        rcall memReadByte
 ramtestr:
        rcall memReadByte

-       mov temp2,adrh
-       eor temp2,adrl
+       mov temp2,xh
+       eor temp2,xl

        cp temp,temp2
        breq ramtestrok
        rcall printhex
        ldi temp,'<'
        rcall uartPutc
        cp temp,temp2
        breq ramtestrok
        rcall printhex
        ldi temp,'<'
        rcall uartPutc

-       mov temp,adrh
-       eor temp,adrl
+       mov temp,xh
+       eor temp,xl

        rcall printhex
        ldi temp,'@'
        rcall uartPutc
        rcall printhex
        ldi temp,'@'
        rcall uartPutc

-       mov temp,adrh
+       mov temp,xh

        rcall printhex
        rcall printhex

-       mov temp,adrl
+       mov temp,xl

        rcall printhex
        ldi temp,13
        rcall uartPutc
 ramtestrok:
        rcall printhex
        ldi temp,13
        rcall uartPutc
 ramtestrok:

-       adiw adrl,1
+       adiw xl,1

        brcc ramtestr
 
 .endif
 
 .if MEMFILL_CB
        ;Fill ram with cbs, which (for now) will trigger an invalid opcode error.
        brcc ramtestr
 
 .endif
 
 .if MEMFILL_CB
        ;Fill ram with cbs, which (for now) will trigger an invalid opcode error.

-       ldi adrl,0
-       ldi adrh,0
+       ldi xl,0
+       ldi xh,0

 ramfillw:
        ldi temp,0xcb
        rcall memwritebyte
 ramfillw:
        ldi temp,0xcb
        rcall memwritebyte

-       adiw adrl,1
+       adiw xl,1

        brcc ramfillw
 .endif
 
 
        brcc ramfillw
 .endif
 
 

+       rcall printstr
+       .db "Initing mmc...",13,0
+       rcall mmcInit
+
+;----------------------------------------------------------------------------
+
+; Partition table offsets:
+#define PART_TYPE   4
+#define PART_START  8
+#define PART_SIZE  12
+
+;Load first sector from MMC (boot sector)
+
+boot_again:
+       ldi     yh,0
+       ldi     yl,0
+       movw    x,y
+       rcall   mmcReadSect
+
+;Test, if it has a valid MBR
+
+       lds     temp,hostbuf+510        ;MBR signature (0xAA55)  at and of sector?
+       lds     temp2,hostbuf+511
+       ldi     temp4,0xAA
+       cpi     temp,0x55               
+       cpc     temp2,temp4
+       ldi     opl,0                   ;opl holds number of found disks (paritions)
+       breq    boot_part
+
+;No MBR, no partition table ...
+       inc     opl                     ;pretend we have one.
+       rjmp    boot_ipl
+               
+;Search Partition Table for CP/M partitions
+boot_part:
+       ldi     zl,low(hostbuf+510-64)
+       ldi     zh,high(hostbuf+510-64)
+       ldi     yl,low(hostparttbl)
+       ldi     yh,high(hostparttbl)
+       ldi     oph,high(hostbuf+510)
+boot_ploop:
+       ldd     temp,z+PART_TYPE
+       cpi     temp,PARTID
+       brne    boot_nextp
+       
+; Found a CP/M partition
+       
+       ldd     temp,z+PART_START
+       st      y+,temp
+       ldd     temp2,z+PART_START+1
+       st      y+,temp2
+       ldd     temp3,z+PART_START+2
+       st      y+,temp3
+       ldd     temp4,z+PART_START+3
+       st      y+,temp4
+       
+       rcall   printstr
+       .db     "CP/M partition at: ",0
+       rcall   print_ultoa
+       rcall   printstr
+       .db     ", size: ",0,0
+       ldd     temp,z+PART_SIZE
+       st      y+,temp
+       ldd     temp2,z+PART_SIZE+1
+       st      y+,temp2
+       ldd     temp3,z+PART_SIZE+2
+       st      y+,temp3
+       ldd     temp4,z+PART_SIZE+3
+       st      y+,temp4
+       lsr     temp4
+       ror     temp3
+       ror     temp2
+       ror     temp
+       rcall   print_ultoa
+       rcall   printstr
+       .db     "KB.",13,0,0
+       
+       inc     opl
+       cpi     opl,MAXDISKS
+       breq    boot_pend       
+boot_nextp:
+       adiw    zl,16
+       cpi     zl,low(hostbuf+510)
+       cpc     zh,oph
+       brsh    boot_pend
+       rjmp    boot_ploop
+boot_pend:
+
+; Read first sector of first CP/M partition
+
+       lds     xl,hostparttbl
+       lds     xh,hostparttbl+1
+       lds     yl,hostparttbl+2
+       lds     yh,hostparttbl+3
+       rcall   mmcReadSect
+
+boot_ipl:
+       sts     ndisks,opl
+       tst     opl
+       brne    boot_ipl2
+       rcall   printstr
+       .db     "No bootable CP/M disk found! Please change MMC/SD-Card",13,0
+       ldi     temp2,18
+boot_wl:
+       ldi     temp,255
+       rcall   delay_ms
+       dec     temp2
+       brne    boot_wl
+       rjmp    boot_again
+       
+
+boot_ipl2:

 
 

-;Load initial sector from MMC (512 bytes)
-       ldi adrh,0
-       ldi adrl,0
-       rcall mmcReadSect
+;First sector of disk or first CP/M partition is in hostbuf.

 
 ;Save to Z80 RAM (only 128 bytes because that's retro)
        ldi zl,low(hostbuf)
        ldi zh,high(hostbuf)
 
 ;Save to Z80 RAM (only 128 bytes because that's retro)
        ldi zl,low(hostbuf)
        ldi zh,high(hostbuf)

-       ldi adrh,0x20
-       ldi adrl,0x00
+       ldi xh,0x20
+       ldi xl,0x00

 iplwriteloop:
        ld temp,z+
        rcall memWriteByte
 iplwriteloop:
        ld temp,z+
        rcall memWriteByte

-       adiw adrl,1
+       adiw xl,1

        cpi zl,low(hostbuf+128)
        brne iplwriteloop
        cpi zh,high(hostbuf+128)
        cpi zl,low(hostbuf+128)
        brne iplwriteloop
        cpi zh,high(hostbuf+128)


@@ -488,18 +604,19 @@ notraceon:
        brsh noprintpc
 
        rcall printstr
        brsh noprintpc
 
        rcall printstr

-       .db "PC=",0
+       .db 13,"PC=",0

        mov temp,z_pch
        rcall printhex
        mov temp,z_pcl
        rcall printhex
        mov temp,z_pch
        rcall printhex
        mov temp,z_pcl
        rcall printhex

-       ldi temp,10
-       rcall uartputc
+       ldi temp,' '
+;      ldi temp,10
+;      rcall uartputc

 noprintpc:
 .endif
 
        ; *** Stage 1: Fetch next opcode
 noprintpc:
 .endif
 
        ; *** Stage 1: Fetch next opcode

-       movw adrl,z_pcl
+       movw xl,z_pcl

        rcall memReadByte
 
 
        rcall memReadByte
 
 


@@ -642,8 +759,8 @@ notrace6:
 ;18    - Sector select
 ;20    - Write addr l
 ;21    - Write addr h
 ;18    - Sector select
 ;20    - Write addr l
 ;21    - Write addr h

-;22    - Trigger - write 1 to read, 2 to write a sector using the above info;
-;                      3 - 5, write to allocated/dirctory/unallocated
+;22    - Trigger - write  to read, to write a sector using the above info;
+;                      , write to allocated/dirctory/unallocated

 
        .equ    READ_FUNC  = 7
        .equ    WRITE_FUNC = 6
 
        .equ    READ_FUNC  = 7
        .equ    WRITE_FUNC = 6


@@ -655,6 +772,7 @@ notrace6:
 ;*****************************************************
 ;*         CP/M to host disk constants               *
 ;*****************************************************
 ;*****************************************************
 ;*         CP/M to host disk constants               *
 ;*****************************************************

+       .equ    MAXDISKS  = 4           ;Max number of Disks (partitions)

        .equ    blksize = 1024          ;CP/M allocation size
        .equ    hostsize = 512          ;host disk sector size
 ;      .equ    hostspt = 20            ;host disk sectors/trk
        .equ    blksize = 1024          ;CP/M allocation size
        .equ    hostsize = 512          ;host disk sector size
 ;      .equ    hostspt = 20            ;host disk sectors/trk


@@ -674,13 +792,15 @@ notrace6:
 
 
        .dseg
 
 
        .dseg

+ndisks:                .byte   1       ;Number of CP/M disks

 
 seekdsk:       .byte   1       ;seek disk number
 seektrk:       .byte   2       ;seek track number
 seeksec:       .byte   1       ;seek sector number
 
 
 seekdsk:       .byte   1       ;seek disk number
 seektrk:       .byte   2       ;seek track number
 seeksec:       .byte   1       ;seek sector number
 

+hostparttbl:   .byte   8*MAXDISKS ; host partition table (start sector, sector count)

 hostdsk:       .byte   1       ;host disk number
 hostdsk:       .byte   1       ;host disk number

-hostlba:       .byte   2       ;host track number
+hostlba:       .byte   3       ;host sector number (relative to partition start)

 
 unacnt:                .byte   1       ;unalloc rec cnt
 unadsk:                .byte   1       ;last unalloc disk
 
 unacnt:                .byte   1       ;unalloc rec cnt
 unadsk:                .byte   1       ;last unalloc disk


@@ -702,6 +822,11 @@ portRead:
        cpi temp2,1
        breq conInp
 
        cpi temp2,1
        breq conInp
 

+       cpi     temp2,15
+       breq    dskDiskCheck
+       cpi     temp2,22
+       breq    dskErrorRet
+

        cpi     temp2,TIMER_MSECS
        brlo    pr_noclock
        cpi     temp2,TIMER_MSECS+6
        cpi     temp2,TIMER_MSECS
        brlo    pr_noclock
        cpi     temp2,TIMER_MSECS+6


@@ -718,6 +843,9 @@ portWrite:
        breq dbgOut
        cpi temp2,2
        breq conOut
        breq dbgOut
        cpi temp2,2
        breq conOut

+
+       cpi temp2,15
+       breq dskDiskSel

        cpi temp2,16
        breq dskTrackSel_l
        cpi temp2,17
        cpi temp2,16
        breq dskTrackSel_l
        cpi temp2,17


@@ -765,6 +893,26 @@ conOut:
        rjmp uartputc
 
 
        rjmp uartputc
 
 

+dskDiskCheck:
+       lds     temp,seekdsk
+       lds     temp2,ndisks    ;check if selected disk # is less then # of disks
+       cp      temp,temp2
+       ldi     temp,0
+       brlt    PC+2
+       ldi     temp,0xff               ;error return
+       ret
+       
+dsk_dchend:
+       ldi     temp,0
+       ret
+       
+dskErrorRet:
+       lds     temp,erflag
+       ret
+
+dskDiskSel:
+       sts seekdsk,temp
+       ret

 
 dskTrackSel_l:
        sts seektrk,temp
 
 dskTrackSel_l:
        sts seektrk,temp


@@ -788,6 +936,52 @@ dskDmah:
        ret
 
 dskDoIt:
        ret
 
 dskDoIt:

+.if DISK_DEBUG
+       push temp
+       sbrc    temp,READ_FUNC
+        rjmp   dskdbgr
+       sbrc    temp,WRITE_FUNC
+        rjmp   dskdbgw
+       rjmp    dskdbge
+
+dskdbgr:
+       rcall printstr
+       .db 13,"Disk read:  ",0
+       rjmp    dskdbg1
+dskdbgw:
+       rcall printstr
+       .db 13,"Disk write: ",0
+dskdbg1:
+       lds     temp,seekdsk
+       subi    temp,-('A')
+       rcall   uartputc
+       rcall   printstr
+       .db     ": track ",0,0
+       lds temp,seektrk+1
+       rcall printhex
+       lds temp,seektrk
+       rcall printhex
+       rcall printstr
+       .db " sector ",0,0
+       lds temp,seeksec
+       rcall printhex
+       rcall printstr
+       .db " dma-addr ",0,0
+       lds temp,dmaadr+1
+       rcall printhex
+       lds temp,dmaadr
+       rcall printhex
+       pop     temp
+       push    temp
+       sbrs    temp,WRITE_FUNC
+        rjmp   dskdbge
+       rcall printstr
+       .db " wrtype ",0,0
+       andi    temp,3
+       rcall printhex
+dskdbge:
+       pop temp
+.endif

        ;See what has to be done.
        sbrc    temp,READ_FUNC
         rjmp   dsk_read
        ;See what has to be done.
        sbrc    temp,READ_FUNC
         rjmp   dsk_read


@@ -816,38 +1010,14 @@ dsk_home:
 
 dsk_read:
 
 
 dsk_read:
 

-.if 0
-       rcall   timer_quit
-       rcall printstr
-       .db " In",0
-.endif
+       sbi     flags,readop            ;read operation
+       ;RAM disk?
+       lds     temp2,seekdsk
+;      cpi     temp2,RAMDISKNR
+;      brlt    PC+2
+;       rjmp   rdskDoIt

 
 

-.if DISK_DEBUG
-       push temp
-       rcall printstr
-       .db 13,0
-       rcall printstr
-       .db "Disk read: track ",0
-       lds temp,seektrk+1
-       rcall printhex
-       lds temp,seektrk
-       rcall printhex
-       rcall printstr
-       .db " sector ",0,0
-       lds temp,seeksec
-       rcall printhex
-       rcall printstr
-       .db " dma-addr ",0,0
-       lds temp,dmaadr+1
-       rcall printhex
-       lds temp,dmaadr
-       rcall printhex
-;      rcall printstr
-;      .db ".",13,0,0
-       pop temp
-.endif

        sts     unacnt,_0
        sts     unacnt,_0

-       sbi     flags,readop            ;read operation

        sbi     flags,rsflag            ;must read data
        ldi     temp,WRUAL              ;write type
        sts     wrtype,temp             ;treat as unalloc
        sbi     flags,rsflag            ;must read data
        ldi     temp,WRUAL              ;write type
        sts     wrtype,temp             ;treat as unalloc


@@ -857,38 +1027,15 @@ dsk_read:
 dsk_write:
        ;write the selected CP/M sector
 
 dsk_write:
        ;write the selected CP/M sector
 

-       andi    temp,WRTMSK
-       sts     wrtype,temp             ;save write type

        cbi     flags,readop            ;not a read operation
 
        cbi     flags,readop            ;not a read operation
 

-.if DISK_DEBUG
-       push temp
-       rcall printstr
-       .db 13,0
-       rcall printstr
-       .db "Disk write: track ",0,0
-       lds temp,seektrk+1
-       rcall printhex
-       lds temp,seektrk
-       rcall printhex
-       rcall printstr
-       .db " sector ",0,0
-       lds temp,seeksec
-       rcall printhex
-       rcall printstr
-       .db " dma-addr ",0,0
-       lds temp,dmaadr+1
-       rcall printhex
-       lds temp,dmaadr
-       rcall printhex
-       rcall printstr
-       .db " wrtype ",0,0
-       lds temp,wrtype
-       rcall printhex
-;      rcall printstr
-;      .db ".",13,0,0
-       pop temp
-.endif
+       ;RAM disk?
+       lds     temp2,seekdsk
+;      cpi     temp2,RAMDISKNR
+;      brlt    PC+2
+;       rjmp   rdskDoIt
+       andi    temp,WRTMSK
+       sts     wrtype,temp             ;save write type

 
        cpi     temp,WRUAL              ;write unallocated?
        brne    dsk_chkuna              ;check for unalloc
 
        cpi     temp,WRUAL              ;write unallocated?
        brne    dsk_chkuna              ;check for unalloc


@@ -964,74 +1111,89 @@ dsk_alloc:
 
 dsk_rwoper:
        ;enter here to perform the read/write
 
 dsk_rwoper:
        ;enter here to perform the read/write

+.if DISK_DEBUG
+       rcall   printstr
+       .db     ", flags: ",0
+       in      temp,flags
+       rcall   printhex
+.endif

        sts     erflag,_0       ;no errors (yet)
 
        ;Convert track/sector to an LBA address (in 128byte blocks)
 
        sts     erflag,_0       ;no errors (yet)
 
        ;Convert track/sector to an LBA address (in 128byte blocks)
 

-       lds     adrl,seeksec            ;
-       ldi     adrh,0                  ;
+       lds     xl,seeksec              ;
+       ldi     xh,0                    ;
+       ldi     yl,0                    ;

        lds     temp3,seektrk           ;
        lds     temp4,seektrk+1         ;
        ldi     temp,CPMSPT             ;
        mul     temp3,temp              ;
        lds     temp3,seektrk           ;
        lds     temp4,seektrk+1         ;
        ldi     temp,CPMSPT             ;
        mul     temp3,temp              ;

-       add     adrl,r0                 ;
-       adc     adrh,r1                 ;
+       add     xl,r0                   ;
+       adc     xh,r1                   ;

        mul     temp4,temp              ;
        mul     temp4,temp              ;

-       add     adrh,r0                 ;adrh:adrl := sec + trk * SectorsPerTrack
+       add     xh,r0                   ;yl:xh:xl := sec + trk * SectorsPerTrack
+       adc     yl,r1                   ;

        clr     _0
 
        clr     _0
 

-       mov     temp,adrl
+       mov     temp,xl

        andi    temp,SECMSK             ;mask buffer number
        push    temp                    ;save for later
        andi    temp,SECMSK             ;mask buffer number
        push    temp                    ;save for later

-.if DISK_DEBUG
-       rcall printstr
-       .db "; bufnr: ",0,0
-       rcall printhex
-.endif

 
        ;Convert from CP/M LBA blocks to host LBA blocks
        ldi temp,SECSHF
 dsk_sh1:
 
        ;Convert from CP/M LBA blocks to host LBA blocks
        ldi temp,SECSHF
 dsk_sh1:

-       lsr     adrh
-       ror     adrl
+       lsr     yl
+       ror     xh
+       ror     xl

        dec     temp
        brne    dsk_sh1
        dec     temp
        brne    dsk_sh1

-                                       ;adrh:adrl = host block to seek
+                                       ;yl:xh:xl = host block to seek

 ;      active host sector?
 ;      active host sector?

-       sbis    flags,hostact           ;host active?
+       in      _tmp,flags              ;host active flag
+       sbi     flags,hostact           ;always becomes 1
+       sbrs    _tmp,hostact            ;was it already?

         rjmp   dsk_filhst              ;fill host if not
 
 ;      host buffer active, same as seek buffer?
        lds     temp,seekdsk
         rjmp   dsk_filhst              ;fill host if not
 
 ;      host buffer active, same as seek buffer?
        lds     temp,seekdsk

-       lds     temp3,hostdsk           ;same disk?
-       cp      temp,temp3              ;seekdsk = hostdsk?
+       lds     temp2,hostdsk           ;same disk?
+       cp      temp,temp2              ;seekdsk = hostdsk?

        brne    dsk_nomatch
 
 ;      same disk, same block?
        brne    dsk_nomatch
 
 ;      same disk, same block?

-       lds     temp3,hostlba
-       lds     temp4,hostlba+1
-       cp      adrl,temp3
-       cpc     adrh,temp4      
+       lds     temp,hostlba
+       lds     temp2,hostlba+1
+       lds     temp3,hostlba+2
+       cp      xl,temp
+       cpc     xh,temp2
+       cpc     yl,temp3

        breq    dsk_match
 ;
 dsk_nomatch:
        ;proper disk, but not correct sector
        breq    dsk_match
 ;
 dsk_nomatch:
        ;proper disk, but not correct sector

-       sbic    flags,hostwrt           ;host written?
+       sbis    flags,hostwrt           ;host written?
+        rjmp   dsk_filhst
+       push    xl
+       push    xh
+       push    yl

         rcall  dsk_writehost           ;clear host buff
         rcall  dsk_writehost           ;clear host buff

+       pop     yl
+       pop     xh
+       pop     xl

 
 dsk_filhst:
        ;may have to fill the host buffer
        lds     temp,seekdsk
        sts     hostdsk,temp
 
 dsk_filhst:
        ;may have to fill the host buffer
        lds     temp,seekdsk
        sts     hostdsk,temp

-       sts     hostlba,adrl
-       sts     hostlba+1,adrh
+       sts     hostlba,xl
+       sts     hostlba+1,xh
+       sts     hostlba+2,yl

 
        sbic    flags,rsflag            ;need to read?
         rcall  dsk_readhost            ;yes, if 1
        cbi     flags,hostwrt           ;no pending write
 
 dsk_match:
 
        sbic    flags,rsflag            ;need to read?
         rcall  dsk_readhost            ;yes, if 1
        cbi     flags,hostwrt           ;no pending write
 
 dsk_match:

-       sbi     flags,hostact           ;host buffer active now

 
        ;copy data to or from buffer
        ldi     zl,low(hostbuf)
 
        ;copy data to or from buffer
        ldi     zl,low(hostbuf)


@@ -1041,7 +1203,7 @@ dsk_match:
        mul     temp2,temp
        add     zl,r0                   ;offset in hostbuf
        adc     zh,r1
        mul     temp2,temp
        add     zl,r0                   ;offset in hostbuf
        adc     zh,r1

-.if DISK_DEBUG
+.if 0 ; DISK_DEBUG

        push    r0
        push    r1
        clr     _0
        push    r0
        push    r1
        clr     _0


@@ -1054,41 +1216,33 @@ dsk_match:
 .endif
        clr     _0
 
 .endif
        clr     _0
 

-       lds     adrl,dmaadr
-       lds     adrh,dmaadr+1
-       push    yl
-       ldi     yl,128                  ;length of move
+       lds     xl,dmaadr
+       lds     xh,dmaadr+1
+       ldi     temp3,128                       ;length of move

        sbic    flags,readop            ;which way?
         rjmp   dsk_rmove               ;skip if read
 
 ;      mark write operation
        sbi     flags,hostwrt           ;hostwrt = 1
 dsk_wmove:
        sbic    flags,readop            ;which way?
         rjmp   dsk_rmove               ;skip if read
 
 ;      mark write operation
        sbi     flags,hostwrt           ;hostwrt = 1
 dsk_wmove:

-       rcall memReadByte
-       st z+,temp
-       adiw adrl,1
-       dec yl
+       rcall   memReadByte
+       st      z+,temp
+       adiw    xl,1
+       dec     temp3

        brne dsk_wmove
        rjmp    dsk_rwmfin
        
 dsk_rmove:
        ld      temp,z+
        rcall   memWriteByte
        brne dsk_wmove
        rjmp    dsk_rwmfin
        
 dsk_rmove:
        ld      temp,z+
        rcall   memWriteByte

-       adiw    adrl,1
-       dec     yl
+       adiw    xl,1
+       dec     temp3

        brne    dsk_rmove
 dsk_rwmfin:
        brne    dsk_rmove
 dsk_rwmfin:

-       pop     yl

 ;      data has been moved to/from host buffer
        lds     temp,wrtype     ;write type
        cpi     temp,WRDIR      ;to directory?
        breq    dsk_wdir
 ;      data has been moved to/from host buffer
        lds     temp,wrtype     ;write type
        cpi     temp,WRDIR      ;to directory?
        breq    dsk_wdir

-       lds     temp,erflag
-.if 0
-       rcall   timer_quit
-       rcall printstr
-       .db " Out",0
-.endif

        ret                     ;no further processing
 dsk_wdir:
 ;      clear host buffer for directory write
        ret                     ;no further processing
 dsk_wdir:
 ;      clear host buffer for directory write


@@ -1099,9 +1253,106 @@ dsk_wdir:
 dsk_wdir1:
        rcall   dsk_writehost   ;clear host buff
        cbi     flags,hostwrt   ;buffer written
 dsk_wdir1:
        rcall   dsk_writehost   ;clear host buff
        cbi     flags,hostwrt   ;buffer written

-       lds     temp,erflag

        ret
 
        ret
 

+;*****************************************************
+
+; hostdsk = host disk #,  (partition #)
+; hostlba = host block #, relative to partition start 
+; Read/Write "hostsize" bytes to/from hostbuf
+       
+
+dsk_hostparam:
+       ldi     zl,low(hostparttbl)
+       ldi     zh,high(hostparttbl)
+       lds     temp,hostdsk
+.if HOSTRW_DEBUG
+       push    temp
+       subi    temp,-('A')
+       rcall   uartputc
+       rcall   printstr
+       .db     ": ",0,0
+       pop     temp
+.endif
+
+       lsl     temp            
+       lsl     temp            
+       lsl     temp            
+       add     zl,temp         
+       adc     zh,_0           
+
+       lds     temp,hostlba
+       lds     temp2,hostlba+1
+       lds     temp3,hostlba+2
+
+.if HOSTRW_DEBUG
+       rcall   printstr
+       .db     "lba: ",0
+       clr     temp4
+       rcall   print_ultoa
+.endif
+
+       ldd     xl,z+4
+       ldd     xh,z+5
+       ldd     yl,z+6
+       
+       cp      temp,xl
+       cpc     temp2,xh
+       cpc     temp3,yl
+       brcs    dsk_hp1
+       
+.if HOSTRW_DEBUG
+       rcall   printstr
+       .db     ", max: ",0
+       push    temp4
+       push    temp3
+       push    temp2
+       push    temp
+       movw    temp,x
+       mov     temp3,yl
+       clr     temp4
+       rcall   print_ultoa
+       pop     temp
+       pop     temp2
+       pop     temp3
+       pop     temp4
+       rcall   printstr
+       .db     " ",0
+.endif
+       
+       clr     temp
+       ret
+
+dsk_hp1:
+       ldd     xl,z+0
+       ldd     xh,z+1
+       ldd     yl,z+2
+       ldd     yh,z+3
+
+       add     xl,temp
+       adc     xh,temp2
+       adc     zl,temp3
+       adc     zh,_0
+.if HOSTRW_DEBUG
+       rcall   printstr
+       .db     ", abs:",0,0
+       push    temp4
+       push    temp3
+       push    temp2
+       push    temp
+       movw    temp,x
+       movw    temp3,y
+       rcall   print_ultoa
+       pop     temp
+       pop     temp2
+       pop     temp3
+       pop     temp4
+       rcall   printstr
+       .db     " ",0
+.endif
+       ori     temp,255
+dsk_hpex:
+       ret

 
 ;*****************************************************
 ;*     WRITEhost performs the physical write to     *
 
 ;*****************************************************
 ;*     WRITEhost performs the physical write to     *


@@ -1110,33 +1361,34 @@ dsk_wdir1:
 ;*****************************************************
 
 dsk_writehost:
 ;*****************************************************
 
 dsk_writehost:

-       ;hostdsk = host disk #, hostlba = host block #.
-       ;Write "hostsize" bytes from hostbuf and return 
-       ;error flag in erflag.
-       ;Return erflag non-zero if error
+.if HOSTRW_DEBUG
+       rcall   printstr
+       .db     13,"host write ",0,0
+.endif
+       rcall   dsk_hostparam
+       brne    dsk_wr1
+       ldi     temp,255
+       sts     erflag,temp
+       ret

        
        

-       push    adrh
-       push    adrl
-       lds     adrl,hostlba
-       lds     adrh,hostlba+1
+dsk_wr1:

        rcall   mmcWriteSect
        rcall   mmcWriteSect

-       pop     adrl
-       pop     adrh

        sts     erflag,_0
        ret
 
 dsk_readhost:
        sts     erflag,_0
        ret
 
 dsk_readhost:

-       ;hostdsk = host disk #, hostlba = host block #.
-       ;Read "hostsiz" bytes into hostbuf and return 
-       ;error flag in erflag.
-
-       push    adrh
-       push    adrl
-       lds     adrl,hostlba
-       lds     adrh,hostlba+1
+.if HOSTRW_DEBUG
+       rcall   printstr
+       .db     13,"host read  ",0,0
+.endif
+       rcall   dsk_hostparam
+       brne    dsk_rd1
+       ldi     temp,255
+       sts     erflag,temp
+       ret
+       
+dsk_rd1:

        rcall   mmcReadSect
        rcall   mmcReadSect

-       pop     adrl
-       pop     adrh

        sts     erflag,_0
        ret
 
        sts     erflag,_0
        ret
 


@@ -1150,8 +1402,6 @@ mmcByteNoSend:
 mmcByte:
 
 .if MMC_DEBUG
 mmcByte:
 
 .if MMC_DEBUG

-       push zl
-       push zh

        rcall printstr
        .db "MMC: <--",0
        rcall printhex
        rcall printstr
        .db "MMC: <--",0
        rcall printhex


@@ -1165,15 +1415,11 @@ mmcWrByteW:
        in temp,SPDR
 
 .if MMC_DEBUG
        in temp,SPDR
 
 .if MMC_DEBUG

-       push temp

        rcall printstr
        .db ", -->",0
        rcall printhex
        rcall printstr
        .db ".",13,0
        rcall printstr
        .db ", -->",0
        rcall printhex
        rcall printstr
        .db ".",13,0

-       pop temp
-       pop zh
-       pop zl

 .endif
        ret
 
 .endif
        ret
 


@@ -1310,8 +1556,8 @@ mmcInitOcrLoopDone:
        ret
 
 
        ret
 
 

-;Call this with adrh:adrl = sector number
-;16bit lba address means a max reach of 32M.
+;Call this with yh:yl:xh:xl = sector number
+;

 mmcReadSect:
        ldi temp,0x50
        out SPCR,temp
 mmcReadSect:
        ldi temp,0x50
        out SPCR,temp


@@ -1320,14 +1566,14 @@ mmcReadSect:
        rcall mmcByteNoSend
        ldi temp,0x51   ;cmd (read sector)
        rcall mmcByte
        rcall mmcByteNoSend
        ldi temp,0x51   ;cmd (read sector)
        rcall mmcByte

-       ldi temp,0
-       lsl adrl
-       rol adrh
-       rol temp
+       lsl     xl                      ;convert to byte address (*512)
+       rol     xh
+       rol     yl
+       mov     temp,yl

        rcall mmcByte
        rcall mmcByte

-       mov temp,adrh ;pxl
+       mov temp,xh ;pxl

        rcall mmcByte
        rcall mmcByte

-       mov temp,adrl ;pyh
+       mov temp,xl ;pyh

        rcall mmcByte
        ldi temp,0  ;pyl
        rcall mmcByte
        rcall mmcByte
        ldi temp,0  ;pyl
        rcall mmcByte


@@ -1366,8 +1612,8 @@ mmcreadloop:
        ret
 
 
        ret
 
 

-;Call this with adrh:adrl = sector number
-;16bit lba address means a max reach of 32M.
+;Call this with yh:yl:xh:xl = sector number
+;

 mmcWriteSect:
        ldi temp,0x50
        out SPCR,temp
 mmcWriteSect:
        ldi temp,0x50
        out SPCR,temp


@@ -1377,14 +1623,14 @@ mmcWriteSect:
 
        ldi temp,0x58   ;cmd (write sector)
        rcall mmcByte
 
        ldi temp,0x58   ;cmd (write sector)
        rcall mmcByte

-       ldi temp,0
-       lsl adrl
-       rol adrh
-       rol temp
+       lsl     xl                      ;convert to byte address (*512)
+       rol     xh
+       rol     yl
+       mov     temp,yl

        rcall mmcByte
        rcall mmcByte

-       mov temp,adrh ;pxl
+       mov temp,xh ;pxl

        rcall mmcByte
        rcall mmcByte

-       mov temp,adrl ;pyh
+       mov temp,xl ;pyh

        rcall mmcByte
        ldi temp,0  ;pyl
        rcall mmcByte
        rcall mmcByte
        ldi temp,0  ;pyl
        rcall mmcByte


@@ -1463,24 +1709,24 @@ resetwait:
        out P_AH,temp
 .endm
 
        out P_AH,temp
 .endm
 

-;Loads the byte on address adrh:adrl into temp.
-;must not alter adrh:adrl
+;Loads the byte on address xh:xl into temp.
+;must not alter xh:xl

 
 dram_read:
        cli
 
 dram_read:
        cli

-       DRAM_SETADDR adrh, ~0,(1<<ram_ras), ~(1<<ram_a8), (1<<ram_oe)
+       DRAM_SETADDR xh, ~0,(1<<ram_ras), ~(1<<ram_a8), (1<<ram_oe)

        cbi P_RAS,ram_ras
        cbi P_RAS,ram_ras

-       DRAM_SETADDR adrl, ~(1<<ram_ras),0, ~((1<<ram_oe)), (1<<ram_a8)
+       DRAM_SETADDR xl, ~(1<<ram_ras),0, ~((1<<ram_oe)), (1<<ram_a8)

        cbi P_CAS,ram_cas
        cbi P_A8,ram_a8
        cbi P_CAS,ram_cas
        cbi P_A8,ram_a8

-       nop
+       dram_wait DRAM_WAITSTATES       ;

        in  temp,P_DQ-2         ; PIN
        sbi P_CAS,ram_cas
 
        cbi P_CAS,ram_cas
        andi temp,0x0f
        swap temp
        in  temp,P_DQ-2         ; PIN
        sbi P_CAS,ram_cas
 
        cbi P_CAS,ram_cas
        andi temp,0x0f
        swap temp

-       nop
+       dram_wait DRAM_WAITSTATES       ;

        in  temp2,P_DQ-2        ; PIN
        andi temp2,0x0f
        or  temp,temp2
        in  temp2,P_DQ-2        ; PIN
        andi temp2,0x0f
        or  temp,temp2


@@ -1493,12 +1739,12 @@ dram_read:
 
 #if DRAM_WORD_ACCESS
 dram_read_w:
 
 #if DRAM_WORD_ACCESS
 dram_read_w:

-       cpi adrl,255
+       cpi xl,255

        brne dram_read_w1
        
        rcall dram_read
        push temp
        brne dram_read_w1
        
        rcall dram_read
        push temp

-       adiw adrl,1
+       adiw xl,1

        rcall dram_read
        mov temp2,temp
        pop temp
        rcall dram_read
        mov temp2,temp
        pop temp


@@ -1506,9 +1752,9 @@ dram_read_w:
 
 dram_read_w1:
        cli
 
 dram_read_w1:
        cli

-       DRAM_SETADDR adrh, ~0,(1<<ram_ras), ~(1<<ram_a8),(1<<ram_oe)
+       DRAM_SETADDR xh, ~0,(1<<ram_ras), ~(1<<ram_a8),(1<<ram_oe)

        cbi P_RAS,ram_ras
        cbi P_RAS,ram_ras

-       DRAM_SETADDR adrl, ~(1<<ram_ras),0, ~((1<<ram_oe)), (1<<ram_a8)
+       DRAM_SETADDR xl, ~(1<<ram_ras),0, ~((1<<ram_oe)), (1<<ram_a8)

        cbi P_CAS,ram_cas
        cbi P_A8,ram_a8
        nop
        cbi P_CAS,ram_cas
        cbi P_A8,ram_a8
        nop


@@ -1525,8 +1771,8 @@ dram_read_w1:
        
 ;      push temp
        mov _wl,temp
        
 ;      push temp
        mov _wl,temp

-       inc adrl
-       DRAM_SETADDR adrl, ~(1<<ram_ras),0, ~((1<<ram_oe)), (1<<ram_a8)
+       inc xl
+       DRAM_SETADDR xl, ~(1<<ram_ras),0, ~((1<<ram_oe)), (1<<ram_a8)

        cbi P_CAS,ram_cas
        cbi P_A8,ram_a8
        nop
        cbi P_CAS,ram_cas
        cbi P_A8,ram_a8
        nop


@@ -1549,8 +1795,8 @@ dram_read_w1:
        ret
 #endif
 
        ret
 #endif
 

-;Writes the byte in temp to  adrh:adrl
-;must not alter adrh:adrl
+;Writes the byte in temp to  xh:xl
+;must not alter xh:xl

 
 dram_write:
        cli
 
 dram_write:
        cli


@@ -1561,9 +1807,9 @@ dram_write:
        andi temp,RAM_DQ_MASK & ~(1<<ram_w)
        ori temp,(1<<ram_cas)
        out PORTC,temp
        andi temp,RAM_DQ_MASK & ~(1<<ram_w)
        ori temp,(1<<ram_cas)
        out PORTC,temp

-       DRAM_SETADDR adrh, ~0,(1<<ram_ras), ~(1<<ram_a8),(1<<ram_oe)
+       DRAM_SETADDR xh, ~0,(1<<ram_ras), ~(1<<ram_a8),(1<<ram_oe)

        cbi P_RAS,ram_ras
        cbi P_RAS,ram_ras

-       DRAM_SETADDR adrl, ~(1<<ram_ras),0, ~((1<<ram_a8)),(1<<ram_oe)
+       DRAM_SETADDR xl, ~(1<<ram_ras),0, ~((1<<ram_a8)),(1<<ram_oe)

        cbi PORTC,ram_cas
        sbi PORTC,ram_cas
 
        cbi PORTC,ram_cas
        sbi PORTC,ram_cas
 


@@ -1585,13 +1831,13 @@ dram_write:
 
 #if DRAM_WORD_ACCESS
 dram_write_w:
 
 #if DRAM_WORD_ACCESS
 dram_write_w:

-       cpi adrl,255
+       cpi xl,255

        brne dram_write_w1
        
        push temp2
        rcall dram_write
        pop temp
        brne dram_write_w1
        
        push temp2
        rcall dram_write
        pop temp

-       adiw adrl,1
+       adiw xl,1

        rcall dram_write
        ret     
 
        rcall dram_write
        ret     
 


@@ -1606,9 +1852,9 @@ dram_write_w1:
        ori temp,(1<<ram_cas)
        out PORTC,temp
 
        ori temp,(1<<ram_cas)
        out PORTC,temp
 

-       DRAM_SETADDR adrh, ~0,(1<<ram_ras), ~(1<<ram_a8),(1<<ram_oe)
+       DRAM_SETADDR xh, ~0,(1<<ram_ras), ~(1<<ram_a8),(1<<ram_oe)

        cbi P_RAS,ram_ras
        cbi P_RAS,ram_ras

-       DRAM_SETADDR adrl, ~(1<<ram_ras),0, ~((1<<ram_a8)),(1<<ram_oe)
+       DRAM_SETADDR xl, ~(1<<ram_ras),0, ~((1<<ram_a8)),(1<<ram_oe)

        cbi PORTC,ram_cas
        sbi PORTC,ram_cas
 
        cbi PORTC,ram_cas
        sbi PORTC,ram_cas
 


@@ -1623,13 +1869,13 @@ dram_write_w1:
        sbi PORTC,ram_cas
 
        pop temp
        sbi PORTC,ram_cas
 
        pop temp

-       inc adrl
+       inc xl

        mov  temp2,temp
        andi temp,RAM_DQ_MASK & ~(1<<ram_w)
        ori temp,(1<<ram_cas)
        out PORTC,temp
 
        mov  temp2,temp
        andi temp,RAM_DQ_MASK & ~(1<<ram_w)
        ori temp,(1<<ram_cas)
        out PORTC,temp
 

-       DRAM_SETADDR adrl, ~(1<<ram_ras),0, ~((1<<ram_a8)),(1<<ram_oe)
+       DRAM_SETADDR xl, ~(1<<ram_ras),0, ~((1<<ram_a8)),(1<<ram_oe)

        cbi PORTC,ram_cas
        sbi PORTC,ram_cas
 
        cbi PORTC,ram_cas
        sbi PORTC,ram_cas
 


@@ -1653,8 +1899,11 @@ dram_write_w1:
 ; ****************************************************************************
 
 ; refresh interupt; exec 2 cbr cycles
 ; ****************************************************************************
 
 ; refresh interupt; exec 2 cbr cycles

-refrint:
-                               ;4      CAS  RAS  
+refrint:                       ;4
+
+       sbis P_RAS,ram_ras      ;2
+       reti
+                               ;       CAS  RAS  

        cbi P_CAS,ram_cas       ;2       1|   1|  
                                ;        1|   1|  
        cbi P_RAS,ram_ras       ;2      |0    1|  
        cbi P_CAS,ram_cas       ;2       1|   1|  
                                ;        1|   1|  
        cbi P_RAS,ram_ras       ;2      |0    1|  


@@ -1663,6 +1912,7 @@ refrint:
 ;      nop                     ;1      |0   |0   
        sbi P_RAS,ram_ras       ;2      |0   |0   
                                ;       |0   |0   
 ;      nop                     ;1      |0   |0   
        sbi P_RAS,ram_ras       ;2      |0   |0   
                                ;       |0   |0   

+       dram_wait DRAM_WAITSTATES-1     ;

 ;      nop                     ;1      |0   |0   
        cbi P_RAS,ram_ras       ;2      |0    1|  
                                ;       |0    1|  
 ;      nop                     ;1      |0   |0   
        cbi P_RAS,ram_ras       ;2      |0    1|  
                                ;       |0    1|  


@@ -1672,7 +1922,6 @@ refrint:
                                ;        1|   1|  
        reti                    ;4  --> 21 cycles
 
                                ;        1|   1|  
        reti                    ;4  --> 21 cycles
 

-; ****************************************************************************

 
 ; ------------- system timer 1ms ---------------
     .dseg
 
 ; ------------- system timer 1ms ---------------
     .dseg


@@ -1966,6 +2215,10 @@ print_ultoa:
        push    yh
        push    yl
        push    z_flags
        push    yh
        push    yl
        push    z_flags

+       push    temp4
+       push    temp3
+       push    temp2
+       push    temp

                                
        clr     yl              ;yl = stack level
 
                                
        clr     yl              ;yl = stack level
 


@@ -2004,6 +2257,10 @@ ultoa6:  pop     temp            ;Flush stacked digits
        dec     yl      
        brne    ultoa6  
 
        dec     yl      
        brne    ultoa6  
 

+       pop     temp
+       pop     temp2
+       pop     temp3
+       pop     temp4

        pop     z_flags
        pop     yl
        pop     yh
        pop     z_flags
        pop     yl
        pop     yh


@@ -2042,8 +2299,8 @@ printstr:
        push    yh
        push    yl
        push    temp
        push    yh
        push    yl
        push    temp

-       in      r29,sph
-       in      r28,spl
+       in      yh,sph
+       in      yl,spl

        ldd     zl,y+7
        ldd     zh,y+6
 
        ldd     zl,y+7
        ldd     zh,y+6
 


@@ -2107,6 +2364,7 @@ rxfifo:
 txfifo:
        .byte   TXBUFSIZE
 
 txfifo:
        .byte   TXBUFSIZE
 

+ramtop:                

        .cseg
 
 ; Save received character in a circular buffer. Do nothing if buffer overflows.
        .cseg
 
 ; Save received character in a circular buffer. Do nothing if buffer overflows.


@@ -2148,7 +2406,7 @@ rxi_ov:                                   ;endif
 uartgetc:
        lds     temp,rxcount            ; Number of characters in buffer
        tst     temp
 uartgetc:
        lds     temp,rxcount            ; Number of characters in buffer
        tst     temp

-       breq    uartgetc
+       breq    uartgetc                ;Wait for char

        
        push    zh
        push    zl
        
        push    zh
        push    zl


@@ -2341,53 +2599,53 @@ do_fetch_sp:
        ret
 
 do_fetch_mbc:
        ret
 
 do_fetch_mbc:

-       movw adrl,z_c
+       movw xl,z_c

        rcall memReadByte
        mov opl,temp
        ret
 
 do_fetch_mde:
        rcall memReadByte
        mov opl,temp
        ret
 
 do_fetch_mde:

-       movw adrl,z_e
+       movw xl,z_e

        rcall memReadByte
        mov opl,temp
        ret
 
 do_fetch_mhl:
        rcall memReadByte
        mov opl,temp
        ret
 
 do_fetch_mhl:

-       movw adrl,z_l
+       movw xl,z_l

        rcall memReadByte
        mov opl,temp
        ret
 
 do_fetch_msp:
        rcall memReadByte
        mov opl,temp
        ret
 
 do_fetch_msp:

-       movw adrl,z_spl
+       movw xl,z_spl

 #if DRAM_WORD_ACCESS
        rcall memReadWord
        movw opl,temp
 #else
        rcall memReadByte
        mov opl,temp
 #if DRAM_WORD_ACCESS
        rcall memReadWord
        movw opl,temp
 #else
        rcall memReadByte
        mov opl,temp

-       adiw adrl,1
+       adiw xl,1

        rcall memReadByte
        mov oph,temp
 #endif 
        ret
 
 do_fetch_dir8:
        rcall memReadByte
        mov oph,temp
 #endif 
        ret
 
 do_fetch_dir8:

-       movw adrl,z_pcl
+       movw xl,z_pcl

        rcall memReadByte
        adiw z_pcl,1
        mov opl,temp
        ret
 
 do_fetch_dir16:
        rcall memReadByte
        adiw z_pcl,1
        mov opl,temp
        ret
 
 do_fetch_dir16:

-       movw adrl,z_pcl
+       movw xl,z_pcl

 #if DRAM_WORD_ACCESS
        rcall memReadWord
        movw opl,temp
 #else
        rcall memReadByte
        mov opl,temp
 #if DRAM_WORD_ACCESS
        rcall memReadWord
        movw opl,temp
 #else
        rcall memReadByte
        mov opl,temp

-       adiw adrl,1
+       adiw xl,1

        rcall memReadByte
        mov oph,temp
 #endif 
        rcall memReadByte
        mov oph,temp
 #endif 


@@ -2395,9 +2653,9 @@ do_fetch_dir16:
        ret
 
 do_fetch_rst:
        ret
 
 do_fetch_rst:

-       movw adrl,z_pcl
-       subi adrl,1
-       sbci adrh,0
+       movw xl,z_pcl
+       subi xl,1
+       sbci xh,0

        rcall memReadByte
        andi temp,0x38
        ldi oph,0
        rcall memReadByte
        andi temp,0x38
        ldi oph,0


@@ -2507,32 +2765,32 @@ do_store_hl:
        ret
 
 do_store_mbc:
        ret
 
 do_store_mbc:

-       movw adrl,z_c
+       movw xl,z_c

        mov temp,opl
        rcall memWriteByte
        ret
 
 do_store_mde:
        mov temp,opl
        rcall memWriteByte
        ret
 
 do_store_mde:

-       movw adrl,z_e
+       movw xl,z_e

        mov temp,opl
        rcall memWriteByte
        ret
 
 do_store_mhl:
        mov temp,opl
        rcall memWriteByte
        ret
 
 do_store_mhl:

-       movw adrl,z_l
+       movw xl,z_l

        mov temp,opl
        rcall memWriteByte
        ret
 
 do_store_msp:
        mov temp,opl
        rcall memWriteByte
        ret
 
 do_store_msp:

-       movw adrl,z_spl
+       movw xl,z_spl

 #if DRAM_WORD_ACCESS
        movw temp,opl
        rcall memWriteWord
 #else
        mov temp,opl
        rcall memWriteByte
 #if DRAM_WORD_ACCESS
        movw temp,opl
        rcall memWriteWord
 #else
        mov temp,opl
        rcall memWriteByte

-       adiw adrl,1
+       adiw xl,1

        mov temp,oph
        rcall memWriteByte
 #endif
        mov temp,oph
        rcall memWriteByte
 #endif


@@ -2561,7 +2819,7 @@ do_store_call:
        ret
 
 do_store_am:
        ret
 
 do_store_am:

-       movw adrl,opl
+       movw xl,opl

        mov temp,z_a
        rcall memWriteByte
        ret
        mov temp,z_a
        rcall memWriteByte
        ret


@@ -2611,6 +2869,8 @@ do_store_am:
 .equ OP_EI             = (38<<10)
 .equ OP_INV            = (39<<10)
 .equ OP_CPFA   = (40<<10)
 .equ OP_EI             = (38<<10)
 .equ OP_INV            = (39<<10)
 .equ OP_CPFA   = (40<<10)

+.equ OP_INCA   = (41<<10)
+.equ OP_DECA   = (42<<10)

 
 opjumps:
        rjmp do_op_nop
 
 opjumps:
        rjmp do_op_nop


@@ -2654,6 +2914,8 @@ opjumps:
        rjmp do_op_ei
        rjmp do_op_inv
        rjmp do_op_cpfa
        rjmp do_op_ei
        rjmp do_op_inv
        rjmp do_op_cpfa

+       rjmp do_op_inca
+       rjmp do_op_deca

 
 
 ;How the flags are supposed to work:
 
 
 ;How the flags are supposed to work:


@@ -2839,13 +3101,13 @@ opjumps:
 ;----------------------------------------------------------------
 
 
 ;----------------------------------------------------------------
 
 

-.equ AVR_T = 6
-.equ AVR_H = 5
-.equ AVR_S = 4
-.equ AVR_V = 3
-.equ AVR_N = 2
-.equ AVR_Z = 1
-.equ AVR_C = 0
+.equ AVR_T = SREG_T
+.equ AVR_H = SREG_H
+.equ AVR_S = SREG_S
+.equ AVR_V = SREG_V
+.equ AVR_N = SREG_N
+.equ AVR_Z = SREG_Z
+.equ AVR_C = SREG_C

 
 ;------------------------------------------------;
 ; Move single bit between two registers
 
 ;------------------------------------------------;
 ; Move single bit between two registers


@@ -2933,15 +3195,27 @@ do_op_nop:
 ;
 ; 
 do_op_inc:
 ;
 ; 
 do_op_inc:

-       ldi     temp,1
-       add     opl,temp
+       inc     opl
+#if EM_Z80

        in      temp, sreg
        in      temp, sreg

+#endif

        andi    z_flags,(1<<ZFL_H)|(1<<ZFL_C)   ; preserve C-, and H-flag
        ldpmx   temp2, sz53p_tab, opl
        or      z_flags,temp2           ;
        do_z80_flags_HP
        ret
 
        andi    z_flags,(1<<ZFL_H)|(1<<ZFL_C)   ; preserve C-, and H-flag
        ldpmx   temp2, sz53p_tab, opl
        or      z_flags,temp2           ;
        do_z80_flags_HP
        ret
 

+do_op_inca:
+       inc     z_a
+#if EM_Z80
+       in      temp, sreg
+#endif
+       andi    z_flags,(1<<ZFL_H)|(1<<ZFL_C)   ; preserve C-, and H-flag
+       ldpmx   temp2, sz53p_tab, z_a
+       or      z_flags,temp2           ;
+       do_z80_flags_HP
+       ret
+

 ;----------------------------------------------------------------
 ;|Mnemonic  |SZHPNC|Description          |Notes                 |
 ;----------------------------------------------------------------
 ;----------------------------------------------------------------
 ;|Mnemonic  |SZHPNC|Description          |Notes                 |
 ;----------------------------------------------------------------


@@ -2954,8 +3228,10 @@ do_op_inc:
 ;
 ;
 do_op_dec:
 ;
 ;
 do_op_dec:

-       subi    opl,1
+       dec     opl
+#if EM_Z80

        in    temp, sreg
        in    temp, sreg

+#endif

        andi    z_flags,(1<<ZFL_H)|(1<<ZFL_C)   ; preserve C-, and H-flag
        ldpmx   temp2, sz53p_tab, opl
        or      z_flags,temp2           ;
        andi    z_flags,(1<<ZFL_H)|(1<<ZFL_C)   ; preserve C-, and H-flag
        ldpmx   temp2, sz53p_tab, opl
        or      z_flags,temp2           ;


@@ -2963,6 +3239,17 @@ do_op_dec:
        do_z80_flags_set_N
        ret
 
        do_z80_flags_set_N
        ret
 

+do_op_deca:
+       dec     z_a
+#if EM_Z80
+       in    temp, sreg
+#endif
+       andi    z_flags,(1<<ZFL_H)|(1<<ZFL_C)   ; preserve C-, and H-flag
+       ldpmx   temp2, sz53p_tab, z_a
+       or      z_flags,temp2           ;
+       do_z80_flags_HP
+       do_z80_flags_set_N
+       ret

 
 ;----------------------------------------------------------------
 ;|Mnemonic  |SZHPNC|Description          |Notes                 |
 
 ;----------------------------------------------------------------
 ;|Mnemonic  |SZHPNC|Description          |Notes                 |


@@ -3222,14 +3509,14 @@ do_op_addhl:
 ;
 ;
 do_op_sthl: ;store hl to mem loc in opl:h
 ;
 ;
 do_op_sthl: ;store hl to mem loc in opl:h

-       movw adrl,opl
+       movw xl,opl

 #if DRAM_WORD_ACCESS
        movw temp,z_l
        rcall memWriteWord
 #else
        mov temp,z_l
        rcall memWriteByte
 #if DRAM_WORD_ACCESS
        movw temp,z_l
        rcall memWriteWord
 #else
        mov temp,z_l
        rcall memWriteByte

-       adiw adrl,1
+       adiw xl,1

        mov temp,z_h
        rcall memWriteByte
 #endif
        mov temp,z_h
        rcall memWriteByte
 #endif


@@ -3242,14 +3529,14 @@ do_op_sthl: ;store hl to mem loc in opl:h
 ;
 ; 
 do_op_rmem16:
 ;
 ; 
 do_op_rmem16:

-       movw adrl,opl
+       movw xl,opl

 #if DRAM_WORD_ACCESS
        rcall memReadWord
        movw opl,temp
 #else
        rcall memReadByte
        mov opl,temp
 #if DRAM_WORD_ACCESS
        rcall memReadWord
        movw opl,temp
 #else
        rcall memReadByte
        mov opl,temp

-       adiw adrl,1
+       adiw xl,1

        rcall memReadByte
        mov oph,temp
 #endif 
        rcall memReadByte
        mov oph,temp
 #endif 


@@ -3262,7 +3549,7 @@ do_op_rmem16:
 ;
 ;
 do_op_rmem8:
 ;
 ;
 do_op_rmem8:

-       movw adrl,opl
+       movw xl,opl

        rcall memReadByte
        mov opl,temp
        ret
        rcall memReadByte
        mov opl,temp
        ret


@@ -3447,17 +3734,17 @@ do_op_cpl:
 ;
 ;
 do_op_push16:
 ;
 ;
 do_op_push16:

-       movw adrl,z_spl
-       subi adrl,2
-       sbci adrh,0
-       movw z_spl,adrl
+       movw xl,z_spl
+       subi xl,2
+       sbci xh,0
+       movw z_spl,xl

 #if DRAM_WORD_ACCESS   
        movw temp,opl
        rcall memWriteWord
 #else
        mov temp,opl
        rcall memWriteByte
 #if DRAM_WORD_ACCESS   
        movw temp,opl
        rcall memWriteWord
 #else
        mov temp,opl
        rcall memWriteByte

-       adiw adrl,1
+       adiw xl,1

        mov temp,oph
        rcall memWriteByte
 #endif
        mov temp,oph
        rcall memWriteByte
 #endif


@@ -3489,14 +3776,14 @@ do_op_push16:
 ;
 ;
 do_op_pop16:
 ;
 ;
 do_op_pop16:

-       movw adrl,z_spl
+       movw xl,z_spl

 #if DRAM_WORD_ACCESS
        rcall memReadWord
        movw opl,temp
 #else
        rcall memReadByte
        mov opl,temp
 #if DRAM_WORD_ACCESS
        rcall memReadWord
        movw opl,temp
 #else
        rcall memReadByte
        mov opl,temp

-       adiw adrl,1
+       adiw xl,1

        rcall memReadByte
        mov oph,temp
 #endif 
        rcall memReadByte
        mov oph,temp
 #endif 


@@ -3852,8 +4139,8 @@ inst_table:
 .dw (FETCH_SP  | OP_ADDHL      | STORE_HL )     ; 39           ADD HL,SP
 .dw (FETCH_DIR16| OP_RMEM8     | STORE_A  )     ; 3A nn nn     LD A,(nn)
 .dw (FETCH_SP  | OP_DEC16      | STORE_SP )     ; 3B           DEC SP
 .dw (FETCH_SP  | OP_ADDHL      | STORE_HL )     ; 39           ADD HL,SP
 .dw (FETCH_DIR16| OP_RMEM8     | STORE_A  )     ; 3A nn nn     LD A,(nn)
 .dw (FETCH_SP  | OP_DEC16      | STORE_SP )     ; 3B           DEC SP

-.dw (FETCH_A    | OP_INC       | STORE_A  )     ; 3C           INC A
-.dw (FETCH_A    | OP_DEC       | STORE_A  )     ; 3D           DEC A
+.dw (FETCH_NOP  | OP_INCA      | STORE_NOP)     ; 3C           INC A
+.dw (FETCH_NOP  | OP_DECA      | STORE_NOP)     ; 3D           DEC A

 .dw (FETCH_DIR8        | OP_NOP        | STORE_A  )     ; 3E nn        LD A,n
 .dw (FETCH_NOP | OP_CCF        | STORE_NOP)     ; 3F           CCF (Complement Carry Flag, gvd)
 .dw (FETCH_B   | OP_NOP        | STORE_B  )     ; 40           LD B,r
 .dw (FETCH_DIR8        | OP_NOP        | STORE_A  )     ; 3E nn        LD A,n
 .dw (FETCH_NOP | OP_CCF        | STORE_NOP)     ; 3F           CCF (Complement Carry Flag, gvd)
 .dw (FETCH_B   | OP_NOP        | STORE_B  )     ; 40           LD B,r