zasm: can now assemble zasm/parse.asm!

This commit is contained in:
Virgil Dupras 2019-05-18 19:59:58 -04:00
parent 2ce6b61964
commit fd11941867
2 changed files with 35 additions and 31 deletions

View File

@ -6,7 +6,7 @@ parseDecimalDigit:
; First, let's see if we have an easy 0-9 case
cp '0'
ret c ; if < '0', we have a problem
sub a, '0' ; our value now is valid if it's < 10
sub '0' ; our value now is valid if it's < 10
cp 10 ; on success, C is set, which is the opposite
; of what we want
ccf ; invert C flag
@ -22,30 +22,27 @@ parseDecimal:
ld ix, 0
.loop:
ld a, (hl)
cp 0
or a
jr z, .end ; success!
call parseDecimalDigit
jr c, .error
; Now, let's add A to IX. First, multiply by 10.
ld d, ixh ; we need a copy of the initial copy for later
ld e, ixl
push ix \ pop de
add ix, ix ; x2
jr c, .error
add ix, ix ; x4
jr c, .error
add ix, ix ; x8
jr c, .error
add ix, de ; x9
jr c, .error
add ix, de ; x10
add a, ixl
jr nc, .nocarry
inc ixh
.nocarry:
ld ixl, a
; We didn't bother checking for the C flag at each step because we
; check for overflow afterwards. If ixh < d, we overflowed
ld a, ixh
cp d
jr c, .error ; carry is set? overflow
jr c, .error
ld d, 0
ld e, a
add ix, de
jr c, .error
inc hl
jr .loop
@ -65,8 +62,8 @@ parseHexadecimal:
call hasHexPrefix
ret nz
push hl
xor a
ld ixh, a
push de
ld d, 0
inc hl ; get rid of "0x"
inc hl
call strlen
@ -82,23 +79,25 @@ parseHexadecimal:
call parseHexPair
jr c, .error
inc hl ; now HL is on first char of next pair
ld ixh, a
ld d, a
jr .single
.doubleShort:
ld a, (hl)
call parseHex
jr c, .error
inc hl ; now HL is on first char of next pair
ld ixh, a
ld d, a
.single:
call parseHexPair
jr c, .error
ld ixl, a
ld e, a
cp a ; ensure Z
jr .end
.error:
call unsetZ
.end:
push de \ pop ix
pop de
pop hl
ret
@ -114,17 +113,17 @@ hasHexPrefix:
pop hl
ret
; Parse string at (HL) as a binary value (0b010101) and return value in IXL.
; Clears IXH.
; Parse string at (HL) as a binary value (0b010101) and return value in IX.
; High IX byte is always clear.
; Sets Z on success.
parseBinaryLiteral:
call hasBinPrefix
ret nz
push bc
push hl
xor a
ld ixh, a
inc hl ; get rid of "0x"
push de
ld d, 0
inc hl ; get rid of "0b"
inc hl
call strlen
or a
@ -148,12 +147,14 @@ parseBinaryLiteral:
inc c
.nobit:
djnz .loop
ld ixl, c
ld e, c
cp a ; ensure Z
jr .end
.error:
call unsetZ
.end:
push de \ pop ix
pop de
pop hl
pop bc
ret
@ -171,7 +172,7 @@ hasBinPrefix:
ret
; Parse string at (HL) and, if it is a char literal, sets Z and return
; corresponding value in IXL. Clears IXH.
; corresponding value in IX. High IX byte is always clear.
;
; A valid char literal starts with ', ends with ' and has one character in the
; middle. No escape sequence are accepted, but ''' will return the apostrophe
@ -182,6 +183,7 @@ parseCharLiteral:
ret nz
push hl
push de
inc hl
inc hl
cp (hl)
@ -191,13 +193,15 @@ parseCharLiteral:
or a ; cp 0
jr nz, .end ; string has to end there
; Valid char, good
ld ixh, a ; A is zero, take advantage of that
ld d, a ; A is zero, take advantage of that
dec hl
dec hl
ld a, (hl)
ld ixl, a
ld e, a
cp a ; ensure Z
.end:
push de \ pop ix
pop de
pop hl
ret
@ -233,8 +237,7 @@ parseNumberOrSymbol:
push de
call symGetVal
; value in DE. We need it in IX
ld ixh, d
ld ixl, e
push de \ pop ix
pop de
cp a ; ensure Z
ret

View File

@ -19,6 +19,7 @@
#include "zasm/io.asm"
.equ SYM_RAMSTART IO_RAMEND
#include "zasm/symbol.asm"
#include "zasm/parse.asm"
zasmIsFirstPass:
nop