; 8080 Interpreter.
; This is part of the Z80-CP/M emulator written by Sprite_tm.
-;
+;
; Copyright (C) 2010 Sprite_tm
; Copyright (C) 2010 Leo C.
;
.dseg
-z_regs:
+z_regs:
z_b: .byte 1
z_c: .byte 1
z_d: .byte 1
#endif
.cseg
-
+
;Init z80
z80_init:
ldi z_pcl,low (IPLADDR)
;
; instr fetch, op, store
;
-.macro instr
+.macro instr
.ifndef opcjmp_table_pos_
.set todo_table_pos_ = PC
; Place the opcode jump table on the next available location.
.equ opcjmp = (PC+255) & 0xff00
.set opcjmp_table_pos_ = opcjmp
.endif
-
+
.if todo_table_pos_ < opcjmp + 256 + 128
.if todo_table_pos_ + 3 >= opcjmp
.set todo_table_pos_ = opcjmp + 256 + 128
.endif
.if cnt_ == 1 ; jump direct to action
- .if fetch_ ;
- rjmp @0 ;
- .endif
+ .if fetch_ ;
+ rjmp @0 ;
+ .endif
.if op_
rjmp do_@1 ; do op and return to main
- .endif
- .if store_ ;
- rjmp @2 ;
- .endif
+ .endif
+ .if store_ ;
+ rjmp @2 ;
+ .endif
.endif
; two or tree actions
.if fetch_ ; must fetch
.if op_ || store_
rcall @0 ; fetch and come back here
- .else ;
+ .else ;
rjmp @0 ; fetch and return to main
.endif
.endif
.endif
.if store_ ; must store
rjmp @2 ; store is allways last
- .endif
-
+ .endif
+
.set todo_table_pos_ = PC
.endif
.endm
-
+
; ------------ Fetch phase stuff -----------------
;.org (PC+255) & 0xff00
fetch_ops:
-do_fetch_nop:
+do_fetch_nop:
ret
do_fetch_a:
store_ops:
do_store_nop:
ret
-
+
do_store_a:
mov z_a,opl
ret
.macro ldpmx
ldi zh,high(@1*2) ; table must be page aligned
- mov zl,@2
- lpm @0,z
+ mov zl,@2
+ lpm @0,z
.endm
.macro do_z80_flags_V
#endif
.endm
-
+
.macro do_z80_flags_copy_HC
#if EM_Z80
bmov z_flags, ZFL_H, z_flags, ZFL_H
do_op_nop:
ret
-
+
;----------------------------------------------------------------
;|Mnemonic |SZHPNC|Description |Notes |
;----------------------------------------------------------------
;|INC r |**-P0-|Increment |r=r+1 |
;|INC [HL] |**-P0-|Increment |[HL]=[HL]+1 |
;
-;
+;
do_op_inc:
ldi temp,1
add opl,temp
;|INC xx |------|Increment |xx=xx+1 |
;|INC ss |------|Increment |ss=ss+1 |
;
-;
+;
do_op_inc16:
subi opl,low(-1)
sbci oph,high(-1)
;|DEC xx |------|Decrement |xx=xx-1 |
;|DEC ss |------|Decrement |ss=ss-1 |
;
-;
+;
do_op_dec16:
subi opl, 1
sbci oph, 0
;
;
do_op_rlca:
- ;Rotate Left Cyclical. All bits move 1 to the
+ ;Rotate Left Cyclical. All bits move 1 to the
;left, the msb becomes c and lsb.
do_z80_flags_op_rotate
lsl z_a
;|RRCA |---- *|Rotate Right Circular|A=->A |
;
;
-do_op_rrca:
- ;Rotate Right Cyclical. All bits move 1 to the
+do_op_rrca:
+ ;Rotate Right Cyclical. All bits move 1 to the
;right, the lsb becomes c and msb.
do_z80_flags_op_rotate
lsr z_a
;|----------|SZHP C|---------- 8080 ----------------------------|
;|RRA |---- *|Rotate Right Acc. |A=->{CY,A} |
;
-;
-do_op_rra:
- ;Rotate Right. All bits move 1 to the right, the lsb
+;
+do_op_rra:
+ ;Rotate Right. All bits move 1 to the right, the lsb
;becomes c, c becomes msb.
clc ; get z80 carry to avr carry
sbrc z_flags,ZFL_C
;|----------|SZHP C|---------- 8080 ----------------------------|
;|RLA |---- *|Rotate Left Acc. |A={CY,A}<- |
;
-;
+;
do_op_rla:
- ;Rotate Left. All bits move 1 to the left, the msb
+ ;Rotate Left. All bits move 1 to the left, the msb
;becomes c, c becomes lsb.
clc
sbrc z_flags,ZFL_C
;----------------------------------------------------------------
;|LD dst,src|------|Load |dst=src |
;
-;
+;
do_op_rmem16:
movw xl,opl
mem_read_d opl
;
; ---------------------
; | N | H | low |H' |
-; | | |nibble | |
+; | | |nibble | |
; |---+---+-------+---|
-; | 0 | * | 0-9 | 0 |
-; | 0 | * | a-f | 1 |
-; | 1 | 0 | * | 0 |
-; | 1 | 1 | 6-f | 0 |
-; | 1 | 1 | 0-5 | 1 |
+; | 0 | * | 0-9 | 0 |
+; | 0 | * | a-f | 1 |
+; | 1 | 0 | * | 0 |
+; | 1 | 1 | 6-f | 0 |
+; | 1 | 1 | 0-5 | 1 |
; ---------------------
;
; Ohter flags:
do_op_da:
#if EM_Z80
- sbrc z_flags,ZFL_N ;if add-op
+ sbrc z_flags,ZFL_N ;if add-op
rjmp op_da_sub ;then
#endif
brlo op_da_a10 ; |
op_da_a01: ; then
ldi oph,0x06 ; add 6 to lower nibble
- add opl,oph ;
- brhc op_da_02 ; if
+ add opl,oph ;
+ brhc op_da_02 ; if
ori temp2,(1<<ZFL_H) ; set new H flag
op_da_02: ;
brcc op_da_a10 ; if
sbrc z_flags,ZFL_C ; |
rjmp op_da_a12 ; if (C flag ...
cpi opl,0xA0 ; |... or upper nibble >= 0xA0)
- brlo op_da_a13 ;
+ brlo op_da_a13 ;
op_da_a12: ;
ldi oph,0x60 ; add 6 to lower nibble
add opl,oph ;
ldi temp2,0 ;new C and H flag
ldi oph,0 ;oph: what to add
- sbrc z_flags,ZFL_N ;if add-op
+ sbrc z_flags,ZFL_N ;if add-op
rjmp op_da_sub ;then
op_da_add:
mov temp,opl ; |
rjmp op_da_a02 ; if (C flag ...
cpi opl,0x90 ; |... or upper nibble >= 0x90)
brlo op_da_a03 ; |
-op_da_a02:
+op_da_a02:
ori oph,0x60 ; add 0x60
ori temp2,(1<<ZFL_C) ; set new C flag
op_da_a03: ; endif
sbrc z_flags,ZFL_C ; |
rjmp op_da_a12 ; if (C flag ...
cpi opl,0xA0 ; |... or upper nibble >= 0xA0)
- brlo op_da_a13 ;
-op_da_a12:
+ brlo op_da_a13 ;
+op_da_a12:
ori oph,0x60 ; add 0x60
ori temp2,(1<<ZFL_C) ; set new C flag
op_da_a13:
;|EX [SP],HL|------|Exchange |[SP]<->HL |
;|EX DE,HL |------|Exchange |DE<->HL |
;-----------------------------Z80--------------------------------
-;
+;
do_op_exhl:
lds temp,z_l
lds temp2,z_h
sbrs z_flags, ZFL_Z
ret
pop temp ; nix tun
- pop temp ; direkt zurueck zu main
+ pop temp ; direkt zurueck zu main
ret
;----------------------------------------------------------------
sbrc z_flags, ZFL_Z
ret
pop temp ; nix tun
- pop temp ; direkt zurueck zu main
+ pop temp ; direkt zurueck zu main
ret
;----------------------------------------------------------------
sbrs z_flags, ZFL_C
ret
pop temp ; nix tun
- pop temp ; direkt zuruech zu main
+ pop temp ; direkt zuruech zu main
ret
;----------------------------------------------------------------
sbrc z_flags, ZFL_C
ret
pop temp ; nix tun
- pop temp ; direkt zuruech zu main
+ pop temp ; direkt zuruech zu main
ret
;----------------------------------------------------------------
sbrs z_flags, ZFL_P
ret
pop temp ; nix tun
- pop temp ; direkt zuruech zu main
+ pop temp ; direkt zuruech zu main
ret
;----------------------------------------------------------------
sbrc z_flags, ZFL_P
ret
pop temp ; nix tun
- pop temp ; direkt zuruech zu main
+ pop temp ; direkt zuruech zu main
ret
;----------------------------------------------------------------
sbrs z_flags, ZFL_S
ret
pop temp ; nix tun
- pop temp ; direkt zuruech zu main
+ pop temp ; direkt zuruech zu main
ret
;----------------------------------------------------------------
sbrc z_flags, ZFL_S
ret
pop temp ; nix tun
- pop temp ; direkt zuruech zu main
+ pop temp ; direkt zuruech zu main
ret
-
+
; ----------------------- Opcode decoding -------------------------
; Lookup table for Z80 opcodes. Translates the first byte of the instruction word into three
; operations: fetch, do something, store.
-; The table is made of 256 words.
+; The table is made of 256 words.
; .org (PC+255) & 0xff00
; Lookup table, stolen from z80ex, Z80 emulation library.
; http://z80ex.sourceforge.net/
-; The S, Z, 5 and 3 bits and the parity of the lookup value
+; The S, Z, 5 and 3 bits and the parity of the lookup value
; .org (PC+255) & 0xff00
.org opcjmp + 256
.db 0xac,0xa8,0xa8,0xac,0xa8,0xac,0xac,0xa8
.db 0xa4,0xa0,0xa0,0xa4,0xa0,0xa4,0xa4,0xa0
.db 0xa8,0xac,0xac,0xa8,0xac,0xa8,0xa8,0xac
-
-; vim:set ts=8 noet nowrap
+; vim:set ts=8 noet nowrap
projects / avrcpm.git / blobdiff