236 lines
4.0 KiB
ArmAsm
236 lines
4.0 KiB
ArmAsm
;
|
|
; utility.s
|
|
; General utilities for 6502
|
|
;
|
|
; Created by Quinn Dunki on 8/15/14.
|
|
; Copyright (c) 2014 One Girl, One Laptop Productions. All rights reserved.
|
|
;
|
|
|
|
|
|
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
|
|
; delayShort
|
|
; Sleeps for ~1/30th second
|
|
;
|
|
delayShort:
|
|
SAVE_AXY
|
|
|
|
ldy #$06 ; Loop a bit
|
|
delayShortOuter:
|
|
ldx #$ff
|
|
delayShortInner:
|
|
nop
|
|
nop
|
|
nop
|
|
nop
|
|
nop
|
|
nop
|
|
nop
|
|
dex
|
|
bne delayShortInner
|
|
dey
|
|
bne delayShortOuter
|
|
|
|
RESTORE_AXY
|
|
rts
|
|
|
|
.if 0
|
|
;;;;;;;;;;;;;;;;;;;;;;;
|
|
; scanHexDigit
|
|
; Scans a 4 bit hex value from an ASCII character
|
|
; A: ASCII character
|
|
; Out A: Hex value
|
|
;
|
|
scanHexDigit:
|
|
cmp #'a'
|
|
bcs scanHexDigitLowCase
|
|
cmp #'A'
|
|
bcs scanHexDigitLetter
|
|
sec
|
|
sbc #'0'
|
|
jmp scanHexDigitDone
|
|
|
|
scanHexDigitLowCase:
|
|
sec
|
|
sbc #32
|
|
|
|
scanHexDigitLetter:
|
|
sec
|
|
sbc #55
|
|
|
|
scanHexDigitDone:
|
|
rts
|
|
|
|
|
|
;;;;;;;;;;;;;;;;;;;;;;;
|
|
; scanHex8
|
|
; Scans an 8 bit hex value from a string
|
|
; PARAM0: Pointer to string (LSB)
|
|
; PARAM1: Pointer to string (MSB)
|
|
; Y: Offset into string
|
|
; Out A: 8-bit hex value
|
|
; Y: One past what we scanned
|
|
; Side effects: Clobbers S0
|
|
;
|
|
scanHex8:
|
|
lda (PARAM0),y
|
|
jsr scanHexDigit
|
|
asl
|
|
asl
|
|
asl
|
|
asl
|
|
sta SCRATCH0 ; Stash first digit for later
|
|
|
|
iny
|
|
lda (PARAM0),y
|
|
jsr scanHexDigit
|
|
ora SCRATCH0
|
|
iny ; Be nice and advance Y to end
|
|
rts
|
|
.endif
|
|
|
|
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
|
|
; WGStrLen
|
|
; Finds the length of a null-terminated string
|
|
; PARAM0: String pointer, LSB
|
|
; PARAM1: String pointer, MSB
|
|
; Return: A: String length, not including null
|
|
;
|
|
WGStrLen:
|
|
phy
|
|
|
|
ldy #$ff
|
|
WGStrLen_loop:
|
|
iny
|
|
lda (PARAM0),y
|
|
bne WGStrLen_loop
|
|
|
|
WGStrLen_done:
|
|
tya
|
|
ply
|
|
rts
|
|
|
|
|
|
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
|
|
; WGAllocStr
|
|
; Finds room in our block string allocator
|
|
; Return: PARAM0: Stored string, LSB
|
|
; PARAM1: Stored string, MSB
|
|
; Null if pool is full
|
|
; X: Pool index of free space
|
|
; Side Effects: Clobbers AX
|
|
;
|
|
WGAllocStr:
|
|
ldx #0
|
|
|
|
WGAllocStr_findEmptyLoop:
|
|
lda WG_STRINGS,x
|
|
beq WGAllocStr_done
|
|
txa
|
|
clc
|
|
adc #16 ; String blocks are 16 bytes wide
|
|
bcs WGAllocStr_noRoom
|
|
tax
|
|
bra WGAllocStr_findEmptyLoop
|
|
|
|
WGAllocStr_noRoom:
|
|
lda #0
|
|
sta PARAM0
|
|
sta PARAM1
|
|
|
|
WGAllocStr_done:
|
|
rts
|
|
|
|
|
|
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
|
|
; WGStoreStr
|
|
; Finds room in our block allocator and copies the given string.
|
|
; A: Terminator character
|
|
; PARAM0: String pointer, LSB
|
|
; PARAM1: String pointer, MSB
|
|
; Return: PARAM0: Stored string, LSB
|
|
; PARAM1: Stored string, MSB
|
|
; Side Effects: Clobbers SA
|
|
;
|
|
WGStoreStr:
|
|
sta WG_SCRATCHA
|
|
SAVE_AXY
|
|
|
|
jsr WGAllocStr
|
|
lda PARAM1
|
|
beq WGStoreStr_done
|
|
ldy #0
|
|
|
|
phx ; Remember the start of our string
|
|
|
|
WGStoreStr_copyLoop:
|
|
lda (PARAM0),y
|
|
cmp WG_SCRATCHA
|
|
beq WGStoreStr_terminate
|
|
sta WG_STRINGS,x
|
|
inx
|
|
iny
|
|
cpy #15 ; Clip string to maximum block size
|
|
bne WGStoreStr_copyLoop
|
|
|
|
WGStoreStr_terminate:
|
|
stz WG_STRINGS,x ; Terminate the stored string
|
|
|
|
pla ; Return pointer to the start of the block
|
|
clc
|
|
adc #<WG_STRINGS
|
|
sta PARAM0
|
|
lda #0
|
|
adc #>WG_STRINGS
|
|
sta PARAM1
|
|
|
|
WGStoreStr_done:
|
|
RESTORE_AXY
|
|
rts
|
|
|
|
|
|
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
|
|
; WGStorePascalStr
|
|
; Finds room in our block allocator and copies the given string.
|
|
; X: Length
|
|
; PARAM0: String pointer, LSB
|
|
; PARAM1: String pointer, MSB
|
|
; Return: PARAM0: Stored string, LSB
|
|
; PARAM1: Stored string, MSB
|
|
; Side Effects: Clobbers SA
|
|
;
|
|
WGStorePascalStr:
|
|
stx WG_SCRATCHA
|
|
SAVE_AXY
|
|
|
|
jsr WGAllocStr
|
|
lda PARAM1
|
|
beq WGStorePascalStr_done
|
|
ldy #0
|
|
|
|
phx ; Remember the start of our string
|
|
|
|
WGStorePascalStr_copyLoop:
|
|
cpy WG_SCRATCHA
|
|
beq WGStorePascalStr_terminate
|
|
lda (PARAM0),y
|
|
sta WG_STRINGS,x
|
|
inx
|
|
iny
|
|
cpy #15 ; Clip string to maximum block size
|
|
bne WGStorePascalStr_copyLoop
|
|
|
|
WGStorePascalStr_terminate:
|
|
stz WG_STRINGS,x ; Terminate the stored string
|
|
|
|
pla ; Return pointer to the start of the block
|
|
clc
|
|
adc #<WG_STRINGS
|
|
sta PARAM0
|
|
lda #0
|
|
adc #>WG_STRINGS
|
|
sta PARAM1
|
|
|
|
WGStorePascalStr_done:
|
|
RESTORE_AXY
|
|
rts
|