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zasm: add support for the "e" arg type (djnz, jr)

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This commit is contained in:
Virgil Dupras 2019-04-17 16:26:04 -04:00
parent c5c8369ce9
commit 76caf944dd
1 changed files with 24 additions and 3 deletions
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27
apps/zasm/zasm.asm
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@ -4,7 +4,7 @@
; Number of rows in the argspec table
ARGSPEC_TBL_CNT .equ 27
; Number of rows in the primary instructions table
INSTR_TBLP_CNT .equ 58
INSTR_TBLP_CNT .equ 64
; size in bytes of each row in the primary instructions table
INSTR_TBLP_ROWSIZE .equ 8
@ -541,6 +541,7 @@ parseLine:
push bc
push af
ld a, (ix+6) ; displacement bit
and a, 0xf ; we only use the lower nibble.
ld b, a
pop af
call rlaX
@ -593,7 +594,15 @@ parseLine:
dec hl ; HL now points to LSB
cp 0
jr nz, .numberTruncated
; Clear to proceed. HL already points to our number
; HL points to our number
; one last thing to check. Is the 7th bit on the displacement value set?
; if yes, we have to decrease our value by 2. Uses for djnz and jr.
bit 7, (ix+6)
jr z, .skipDecrease
; Yup, it's set.
dec (hl)
dec (hl)
.skipDecrease:
inc de
ldi
ld a, 2
@ -684,8 +693,14 @@ argGrpABCDEHL:
; 4 bytes for the name (fill with zero)
; 1 byte for arg constant
; 1 byte for 2nd arg constant
; 1 byte displacement for group arguments
; 1 byte displacement for group arguments + flags
; 1 byte for upcode
;
; The displacement bit is split in 2 nibbles: lower nibble is the displacement
; value, upper nibble is for flags. There is one flag currently, on bit 7, that
; indicates that the numerical argument is of the 'e' type and has to be
; decreased by 2 (djnz, jr).
instrTBlPrimary:
.db "ADD", 0, 'A', 'h', 0, 0x86 ; ADD A, HL
.db "ADD", 0, 'A', 0xb, 0, 0b10000000 ; ADD A, r
@ -703,6 +718,7 @@ instrTBlPrimary:
.db "DEC", 0, 'l', 0, 0, 0x35 ; DEC (HL)
.db "DEC", 0, 0xb, 0, 3, 0b00000101 ; DEC r
.db "DEC", 0, 0x3, 0, 4, 0b00001011 ; DEC s
.db "DJNZ", 'n', 0,0x80, 0x10 ; DJNZ e
.db "EI",0,0, 0, 0, 0, 0xfb ; EI
.db "EX",0,0, 'p', 'h', 0, 0xe3 ; EX (SP), HL
.db "EX",0,0, 'a', 'f', 0, 0x08 ; EX AF, AF'
@ -715,6 +731,11 @@ instrTBlPrimary:
.db "INC", 0, 0x3, 0, 4, 0b00000011 ; INC s
.db "JP",0,0, 'l', 0, 0, 0xe9 ; JP (HL)
.db "JP",0,0, 'N', 0, 0, 0xc3 ; JP NN
.db "JR",0,0, 'n', 0,0x80, 0x18 ; JR e
.db "JR",0,0,'^','n',0x80, 0x38 ; JR C, e
.db "JR",0,0,'=','n',0x80, 0x30 ; JR NC, e
.db "JR",0,0,'Z','n',0x80, 0x28 ; JR Z, e
.db "JR",0,0,'z','n',0x80, 0x20 ; JR NZ, e
.db "LD",0,0, 'c', 'A', 0, 0x02 ; LD (BC), A
.db "LD",0,0, 'e', 'A', 0, 0x12 ; LD (DE), A
.db "LD",0,0, 'A', 'c', 0, 0x0a ; LD A, (BC)