From 7969d1d050a00a45087b48c7c87333022d691763 Mon Sep 17 00:00:00 2001
From: Leo <erbl259-lmu@yahoo.de>
Date: Fri, 6 Aug 2010 10:08:56 +0000
Subject: [PATCH] * avr/z80.asm:   - Added a RAM disk

git-svn-id: svn://cu.loc/avr-cpm/trunk@70 57430480-672e-4586-8877-bcf8adbbf3b7
---
 avrcpm/avr/z80.asm | 203 ++++++++++++++++++++++++++++++++++++++-------
 1 file changed, 175 insertions(+), 28 deletions(-)

diff --git a/avrcpm/avr/z80.asm b/avrcpm/avr/z80.asm
index 4b0e507..2c54bab 100644
--- a/avrcpm/avr/z80.asm
+++ b/avrcpm/avr/z80.asm
@@ -45,6 +45,8 @@
  
 #define PARTID 0x52		/* Partition table id */
 				/* http://www.win.tue.nl/~aeb/partitions/partition_types-1.html */
+#define RAMDISKNR 'I'-'A'	/* Driveletter for first RAM disk */
+#define RAMDISKCNT 1		/* Number of RAM disks */
 
 #define UBRR_VAL  ((F_CPU+BAUD*8)/(BAUD*16)-1)  /* clever rounding */
 
@@ -249,6 +251,27 @@
 
 
 
+; -------------------- DRAM ---------------
+
+; DRAM_SETADDR val, low_and_mask, low_or_mask, high_and_mask, high_or_mask
+.macro DRAM_SETADDR
+	mov temp,@0
+.if low(@1) != 0xff
+	andi temp,@1
+.endif
+.if  low(@2) != 0
+	ori temp, @2
+.endif
+	out P_AL,temp
+	
+	mov temp,@0
+.if low(@3) != 0xff
+	andi temp,@3
+.endif
+	ori temp, @4 | (1<<mmc_cs)
+	out P_AH,temp
+.endm
+
 ;----------------------------------------
 ; add wait states
 ;	dram_wait  number_of_cycles
@@ -909,8 +932,13 @@ 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
+	brlt	dsk_dchend
+	
+	cpi	temp,RAMDISKNR
+	brlt	dsk_dcher
+	cpi	temp,RAMDISKNR+RAMDISKCNT
+	brlt	dsk_dchend
+dsk_dcher:
 	ldi	temp,0xff		;error return
 	ret
 	
@@ -1028,9 +1056,9 @@ dsk_read:
 	sbi	flags,readop		;read operation
 	;RAM disk?
 	lds	temp2,seekdsk
-;	cpi	temp2,RAMDISKNR
-;	brlt	PC+2
-;	 rjmp	rdskDoIt
+	cpi	temp2,RAMDISKNR
+	brlt	PC+2
+	 rjmp	rdskDoIt
 
 	sts	unacnt,_0
 	sbi	flags,rsflag		;must read data
@@ -1046,9 +1074,9 @@ dsk_write:
 
 	;RAM disk?
 	lds	temp2,seekdsk
-;	cpi	temp2,RAMDISKNR
-;	brlt	PC+2
-;	 rjmp	rdskDoIt
+	cpi	temp2,RAMDISKNR
+	brlt	PC+2
+	 rjmp	rdskDoIt
 	andi	temp,WRTMSK
 	sts	wrtype,temp		;save write type
 
@@ -1408,6 +1436,144 @@ dsk_rd1:
 	ret
 
 
+;***************************************************************************
+; ----------------- RAM disk -----------------
+
+	.dseg
+rdskbuf:
+	.byte	128
+	
+	.cseg
+;----------------------------------------------
+
+rdsk_adr:
+	ldi	xl,0
+	lds	xh,seeksec
+	lds	temp2,seektrk
+	
+	lsr	xh
+	ror	xl			;Col 0..7
+	
+	mov	temp,temp2
+	andi	temp,0x0f
+	swap	temp
+	or	xh,temp			;Row  0..7
+	
+	ldi	zl,low (rdskbuf)
+	ldi	zh,high(rdskbuf)
+	ldi	temp3,128
+	DRAM_SETADDR xh, ~0,(1<<ram_ras), ~0,(1<<ram_a8)|(1<<ram_oe)
+	cbi	P_RAS,ram_ras
+
+.if DISK_DEBUG
+	mov	temp,xh
+	rcall	printhex
+	rcall	printstr
+	.db	" ",0
+	mov	temp,xl
+	rcall	printhex
+	rcall	printstr
+	.db	" ",0
+.endif
+	ret
+
+;----------------------------------------------
+
+rdskDoIt:
+	sts	erflag,_0
+	sbis	flags,readop
+	 rjmp	rdsk_wr
+	
+.if DISK_DEBUG
+	rcall	printstr
+	.db	13,"rd-adr: ",0
+.endif
+	rcall	rdsk_adr
+rdsk_rdl:
+	DRAM_SETADDR xl, ~(1<<ram_ras),0, ~((1<<ram_oe)), (1<<ram_a8)
+	cbi	P_CAS,ram_cas
+	cbi	P_A8,ram_a8
+	inc	xl
+	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
+	dram_wait DRAM_WAITSTATES	;
+	in	temp2,P_DQ-2	; PIN
+	andi	temp2,0x0f
+	or	temp,temp2
+
+	sbi	P_OE,ram_oe
+	sbi	P_CAS,ram_cas
+	dec	temp3
+	st	z+,temp
+	brne	rdsk_rdl
+
+	sbi	P_RAS,ram_ras
+	ldi	zl,low (rdskbuf)
+	ldi	zh,high(rdskbuf)
+	lds	xl,dmaadr
+	lds	xh,dmaadr+1
+	ldi	temp3,128	
+rdsk_rdstl:
+	ld	temp,z+
+	rcall	dram_write
+	adiw	x,1
+	dec	temp3
+	brne	rdsk_rdstl
+	ret
+	
+
+rdsk_wr:
+.if DISK_DEBUG
+	rcall	printstr
+	.db	13,"wr-adr: ",0
+.endif	
+	lds	xl,dmaadr
+	lds	xh,dmaadr+1
+	ldi	zl,low (rdskbuf)
+	ldi	zh,high(rdskbuf)
+	ldi	temp3,128	
+rdsk_wrldl:
+	rcall	dram_read
+	st	z+,temp
+	adiw	x,1
+	dec	temp3
+	brne	rdsk_wrldl	
+
+	ldi	temp2,RAM_DQ_MASK | (1<<ram_w) | (1<<ram_cas)
+	out	DDRC,temp2
+	rcall	rdsk_adr
+rdsk_wrl:
+	ld	temp,z+
+	mov	temp2,temp
+	andi	temp,RAM_DQ_MASK & ~(1<<ram_w)
+	ori	temp,(1<<ram_cas)
+	out	PORTC,temp
+	DRAM_SETADDR xl, ~(1<<ram_ras),0, ~((1<<ram_a8)),(1<<ram_oe)
+	cbi	PORTC,ram_cas
+	sbi	PORTD,ram_a8
+	sbi	PORTC,ram_cas
+	swap	temp2
+	andi	temp2,RAM_DQ_MASK & ~(1<<ram_w)
+	ori	temp2,(1<<ram_cas)
+	out	PORTC,temp2
+	cbi	PORTC,ram_cas
+	inc	xl
+	sbi	PORTC,ram_cas
+	dec	temp3
+	brne	rdsk_wrl
+
+	sbi	P_RAS,ram_ras
+	ldi	temp,~RAM_DQ_MASK | (1<<ram_w) | (1<<ram_cas)
+	out	DDRC,temp
+	out	PORTC,temp
+	ret
+	
+
 ;***************************************************************************
 
 ; ----------------- MMC/SD routines ------------------
@@ -1705,25 +1871,6 @@ resetwait:
 
 ; ------------------ DRAM routines -------------
 
-; DRAM_SETADDR val, low_and_mask, low_or_mask, high_and_mask, high_or_mask
-.macro DRAM_SETADDR
-	mov temp,@0
-.if low(@1) != 0xff
-	andi temp,@1
-.endif
-.if  low(@2) != 0
-	ori temp, @2
-.endif
-	out P_AL,temp
-	
-	mov temp,@0
-.if low(@3) != 0xff
-	andi temp,@3
-.endif
-	ori temp, @4 | (1<<mmc_cs)
-	out P_AH,temp
-.endm
-
 ;Loads the byte on address xh:xl into temp.
 ;must not alter xh:xl
 
@@ -2379,7 +2526,7 @@ rxfifo:
 txfifo:
 	.byte	TXBUFSIZE
 
-ramtop:		
+ramtop:	.byte	0	
 	.cseg
 
 ; Save received character in a circular buffer. Do nothing if buffer overflows.
-- 
2.39.2