mirror of https://github.com/hsoft/collapseos.git
117 lines
2.1 KiB
NASM
117 lines
2.1 KiB
NASM
; run RLA the number of times specified in B
|
|
rlaX:
|
|
; first, see if B == 0 to see if we need to bail out
|
|
inc b
|
|
dec b
|
|
ret z ; Z flag means we had B = 0
|
|
.loop: rla
|
|
djnz .loop
|
|
ret
|
|
|
|
callHL:
|
|
jp (hl)
|
|
ret
|
|
|
|
; Compare HL with DE and sets Z and C in the same way as a regular cp X where
|
|
; HL is A and DE is X.
|
|
cpHLDE:
|
|
ld a, h
|
|
cp d
|
|
ret nz ; if not equal, flags are correct
|
|
ld a, l
|
|
cp e
|
|
ret ; flags are correct
|
|
|
|
; HL - DE -> HL
|
|
subDEFromHL:
|
|
push af
|
|
ld a, l
|
|
sub e
|
|
ld l, a
|
|
ld a, h
|
|
sbc d
|
|
ld h, a
|
|
pop af
|
|
ret
|
|
|
|
; Returns length of string at (HL) in A.
|
|
strlen:
|
|
push bc
|
|
push hl
|
|
ld bc, 0
|
|
ld a, 0 ; look for null char
|
|
.loop:
|
|
cpi
|
|
jp z, .found
|
|
jr .loop
|
|
.found:
|
|
; How many char do we have? the (NEG BC)-1, which started at 0 and
|
|
; decreased at each CPI call. In this routine, we stay in the 8-bit
|
|
; realm, so C only.
|
|
ld a, c
|
|
neg
|
|
dec a
|
|
pop hl
|
|
pop bc
|
|
ret
|
|
|
|
; If string at (HL) starts with ( and ends with ), "enter" into the parens
|
|
; (advance HL and put a null char at the end of the string) and set Z.
|
|
; Otherwise, do nothing and reset Z.
|
|
enterParens:
|
|
ld a, (hl)
|
|
cp '('
|
|
ret nz ; nothing to do
|
|
push hl
|
|
ld a, 0 ; look for null char
|
|
; advance until we get null
|
|
.loop:
|
|
cpi
|
|
jp z, .found
|
|
jr .loop
|
|
.found:
|
|
dec hl ; cpi over-advances. go back to null-char
|
|
dec hl ; looking at the last char before null
|
|
ld a, (hl)
|
|
cp ')'
|
|
jr nz, .doNotEnter
|
|
; We have parens. While we're here, let's put a null
|
|
xor a
|
|
ld (hl), a
|
|
pop hl ; back at the beginning. Let's advance.
|
|
inc hl
|
|
cp a ; ensure Z
|
|
ret ; we're good!
|
|
.doNotEnter:
|
|
pop hl
|
|
call JUMP_UNSETZ
|
|
ret
|
|
|
|
; Find string (HL) in string list (DE) of size B. Each string is C bytes wide.
|
|
; Returns the index of the found string. Sets Z if found, unsets Z if not found.
|
|
findStringInList:
|
|
push de
|
|
push bc
|
|
.loop:
|
|
ld a, c
|
|
call JUMP_STRNCMP
|
|
ld a, c
|
|
call JUMP_ADDDE
|
|
jr z, .match
|
|
djnz .loop
|
|
; no match, Z is unset
|
|
pop bc
|
|
pop de
|
|
ret
|
|
.match:
|
|
; Now, we want the index of our string, which is equal to our initial B
|
|
; minus our current B. To get this, we have to play with our registers
|
|
; and stack a bit.
|
|
ld d, b
|
|
pop bc
|
|
ld a, b
|
|
sub d
|
|
pop de
|
|
cp a ; ensure Z
|
|
ret
|