collapseos/apps/zasm/parse.asm
Virgil Dupras 0bd58fd178 basic: parse hex, binary and char literals
Same thing as in zasm.
2019-11-18 15:22:09 -05:00

45 lines
1.1 KiB
NASM

; Parse string in (HL) and return its numerical value whether its a number
; literal or a symbol. Returns value in IX.
; Sets Z if number or symbol is valid, unset otherwise.
parseNumberOrSymbol:
call parseLiteral
ret z
; Not a number.
; Is str a single char? If yes, maybe it's a special symbol.
call strIs1L
jr nz, .symbol ; nope
ld a, (hl)
cp '$'
jr z, .returnPC
cp '@'
jr nz, .symbol
; last val
ld ix, (DIREC_LASTVAL)
ret
.symbol:
push de ; --> lvl 1
call symFindVal ; --> DE
jr nz, .notfound
; value in DE. We need it in IX
push de \ pop ix
pop de ; <-- lvl 1
cp a ; ensure Z
ret
.notfound:
pop de ; <-- lvl 1
; If not found, check if we're in first pass. If we are, it doesn't
; matter that we didn't find our symbol. Return success anyhow.
; Otherwise return error. Z is already unset, so in fact, this is the
; same as jumping to zasmIsFirstPass
; however, before we do, load IX with zero. Returning dummy non-zero
; values can have weird consequence (such as false overflow errors).
ld ix, 0
jp zasmIsFirstPass
.returnPC:
push hl
call zasmGetPC
push hl \ pop ix
pop hl
ret