mirror of
https://github.com/irmen/prog8.git
synced 2024-12-25 23:29:55 +00:00
4958463e75
added txt.print_f as alias to floats.print
669 lines
18 KiB
Lua
669 lines
18 KiB
Lua
; Prog8 definitions for the Commodore PET
|
|
; Including memory registers, I/O registers, Basic and Kernal subroutines.
|
|
; see: https://www.pagetable.com/?p=926 , http://www.zimmers.net/cbmpics/cbm/PETx/petmem.txt
|
|
|
|
%option no_symbol_prefixing, ignore_unused
|
|
|
|
cbm {
|
|
; Commodore (CBM) common variables, vectors and kernal routines
|
|
|
|
&ubyte TIME_HI = $8d ; software jiffy clock, hi byte
|
|
&ubyte TIME_MID = $8e ; .. mid byte
|
|
&ubyte TIME_LO = $8f ; .. lo byte. Updated by IRQ every 1/60 sec
|
|
&ubyte STATUS = $96 ; kernal status variable for I/O
|
|
|
|
&uword CINV = $0090 ; IRQ vector (in ram)
|
|
&uword CBINV = $0092 ; BRK vector (in ram)
|
|
&uword NMINV = $0094 ; NMI vector (in ram)
|
|
|
|
&uword NMI_VEC = $FFFA ; 6502 nmi vector, determined by the kernal if banked in
|
|
&uword RESET_VEC = $FFFC ; 6502 reset vector, determined by the kernal if banked in
|
|
&uword IRQ_VEC = $FFFE ; 6502 interrupt vector, determined by the kernal if banked in
|
|
|
|
; the default addresses for the character screen chars and colors
|
|
const uword Screen = $8000 ; to have this as an array[40*25] the compiler would have to support array size > 255
|
|
|
|
|
|
extsub $FFC6 = CHKIN(ubyte logical @ X) clobbers(A,X) -> bool @Pc ; define an input channel
|
|
extsub $FFC9 = CHKOUT(ubyte logical @ X) clobbers(A,X) ; define an output channel
|
|
extsub $FFCC = CLRCHN() clobbers(A,X) ; restore default devices
|
|
extsub $FFCF = CHRIN() clobbers(X, Y) -> ubyte @ A ; input a character (for keyboard, read a whole line from the screen) A=byte read.
|
|
extsub $FFD2 = CHROUT(ubyte character @ A) ; output a character
|
|
extsub $FFE1 = STOP() clobbers(X) -> bool @ Pz, ubyte @ A ; check the STOP key (and some others in A) also see STOP2
|
|
extsub $FFE4 = GETIN() clobbers(X,Y) -> bool @Pc, ubyte @ A ; get a character also see GETIN2
|
|
extsub $FFE7 = CLALL() clobbers(A,X) ; close all files
|
|
extsub $FFEA = UDTIM() clobbers(A,X) ; update the software clock
|
|
|
|
|
|
inline asmsub STOP2() clobbers(X,A) -> bool @Pz {
|
|
; -- just like STOP, but omits the special keys result value in A.
|
|
; just for convenience because most of the times you're only interested in the stop pressed or not status.
|
|
%asm {{
|
|
jsr cbm.STOP
|
|
}}
|
|
}
|
|
|
|
inline asmsub GETIN2() clobbers(X,Y) -> ubyte @A {
|
|
; -- just like GETIN, but omits the carry flag result value.
|
|
; just for convenience because GETIN is so often used to just read keyboard input,
|
|
; where you don't have to deal with a potential error status
|
|
%asm {{
|
|
jsr cbm.GETIN
|
|
}}
|
|
}
|
|
|
|
asmsub SETTIM(ubyte low @ A, ubyte middle @ X, ubyte high @ Y) {
|
|
; PET stub to set the software clock
|
|
%asm {{
|
|
sty TIME_HI
|
|
stx TIME_MID
|
|
sta TIME_LO
|
|
rts
|
|
}}
|
|
}
|
|
|
|
asmsub RDTIM() -> ubyte @ A, ubyte @ X, ubyte @ Y {
|
|
; PET stub to read the software clock (A=lo,X=mid,Y=high)
|
|
%asm {{
|
|
ldy TIME_HI
|
|
ldx TIME_MID
|
|
lda TIME_LO
|
|
rts
|
|
}}
|
|
}
|
|
|
|
asmsub RDTIM16() clobbers(X) -> uword @AY {
|
|
; -- like RDTIM() but only returning the lower 16 bits in AY for convenience
|
|
%asm {{
|
|
lda TIME_LO
|
|
ldy TIME_MID
|
|
rts
|
|
}}
|
|
}
|
|
|
|
asmsub kbdbuf_clear() {
|
|
; -- convenience helper routine to clear the keyboard buffer
|
|
%asm {{
|
|
- jsr GETIN
|
|
cmp #0
|
|
bne -
|
|
rts
|
|
}}
|
|
}
|
|
|
|
}
|
|
|
|
sys {
|
|
; ------- lowlevel system routines --------
|
|
|
|
const ubyte target = 32 ; compilation target specifier. 255=virtual, 128=C128, 64=C64, 32=PET, 16=CommanderX16, 8=atari800XL, 7=Neo6502
|
|
|
|
const ubyte SIZEOF_BOOL = 1
|
|
const ubyte SIZEOF_BYTE = 1
|
|
const ubyte SIZEOF_UBYTE = 1
|
|
const ubyte SIZEOF_WORD = 2
|
|
const ubyte SIZEOF_UWORD = 2
|
|
const ubyte SIZEOF_FLOAT = 0 ; undefined, no floats supported
|
|
const byte MIN_BYTE = -128
|
|
const byte MAX_BYTE = 127
|
|
const ubyte MIN_UBYTE = 0
|
|
const ubyte MAX_UBYTE = 255
|
|
const word MIN_WORD = -32768
|
|
const word MAX_WORD = 32767
|
|
const uword MIN_UWORD = 0
|
|
const uword MAX_UWORD = 65535
|
|
; MIN_FLOAT and MAX_FLOAT are defined in the floats module if imported
|
|
|
|
|
|
asmsub reset_system() {
|
|
; Soft-reset the system back to initial power-on Basic prompt.
|
|
%asm {{
|
|
sei
|
|
jmp (cbm.RESET_VEC)
|
|
}}
|
|
}
|
|
|
|
asmsub waitvsync() clobbers(A) {
|
|
; --- busy wait till the next vsync has occurred (approximately), without depending on custom irq handling.
|
|
; Note: on PET this simply waits until the next jiffy clock update, I don't know if a true vsync is possible there
|
|
%asm {{
|
|
lda #1
|
|
ldy #0
|
|
jmp wait
|
|
}}
|
|
}
|
|
|
|
asmsub wait(uword jiffies @AY) {
|
|
; --- wait approximately the given number of jiffies (1/60th seconds) (N or N+1)
|
|
; note: the system irq handler has to be active for this to work as it depends on the system jiffy clock
|
|
%asm {{
|
|
stx P8ZP_SCRATCH_B1
|
|
sta P8ZP_SCRATCH_W1
|
|
sty P8ZP_SCRATCH_W1+1
|
|
|
|
_loop lda P8ZP_SCRATCH_W1
|
|
ora P8ZP_SCRATCH_W1+1
|
|
bne +
|
|
ldx P8ZP_SCRATCH_B1
|
|
rts
|
|
|
|
+ lda cbm.TIME_LO
|
|
sta P8ZP_SCRATCH_B1
|
|
- lda cbm.TIME_LO
|
|
cmp P8ZP_SCRATCH_B1
|
|
beq -
|
|
|
|
lda P8ZP_SCRATCH_W1
|
|
bne +
|
|
dec P8ZP_SCRATCH_W1+1
|
|
+ dec P8ZP_SCRATCH_W1
|
|
jmp _loop
|
|
}}
|
|
}
|
|
|
|
asmsub internal_stringcopy(uword source @R0, uword target @AY) clobbers (A,Y) {
|
|
; Called when the compiler wants to assign a string value to another string.
|
|
%asm {{
|
|
sta P8ZP_SCRATCH_W1
|
|
sty P8ZP_SCRATCH_W1+1
|
|
lda cx16.r0
|
|
ldy cx16.r0+1
|
|
jmp prog8_lib.strcpy
|
|
}}
|
|
}
|
|
|
|
asmsub memcopy(uword source @R0, uword target @R1, uword count @AY) clobbers(A,X,Y) {
|
|
; note: only works for NON-OVERLAPPING memory regions!
|
|
; note: can't be inlined because is called from asm as well
|
|
%asm {{
|
|
ldx cx16.r0
|
|
stx P8ZP_SCRATCH_W1 ; source in ZP
|
|
ldx cx16.r0+1
|
|
stx P8ZP_SCRATCH_W1+1
|
|
ldx cx16.r1
|
|
stx P8ZP_SCRATCH_W2 ; target in ZP
|
|
ldx cx16.r1+1
|
|
stx P8ZP_SCRATCH_W2+1
|
|
cpy #0
|
|
bne _longcopy
|
|
|
|
; copy <= 255 bytes
|
|
tay
|
|
bne _copyshort
|
|
rts ; nothing to copy
|
|
|
|
_copyshort
|
|
dey
|
|
beq +
|
|
- lda (P8ZP_SCRATCH_W1),y
|
|
sta (P8ZP_SCRATCH_W2),y
|
|
dey
|
|
bne -
|
|
+ lda (P8ZP_SCRATCH_W1),y
|
|
sta (P8ZP_SCRATCH_W2),y
|
|
rts
|
|
|
|
_longcopy
|
|
sta P8ZP_SCRATCH_B1 ; lsb(count) = remainder in last page
|
|
tya
|
|
tax ; x = num pages (1+)
|
|
ldy #0
|
|
- lda (P8ZP_SCRATCH_W1),y
|
|
sta (P8ZP_SCRATCH_W2),y
|
|
iny
|
|
bne -
|
|
inc P8ZP_SCRATCH_W1+1
|
|
inc P8ZP_SCRATCH_W2+1
|
|
dex
|
|
bne -
|
|
ldy P8ZP_SCRATCH_B1
|
|
bne _copyshort
|
|
rts
|
|
}}
|
|
}
|
|
|
|
asmsub memset(uword mem @R0, uword numbytes @R1, ubyte value @A) clobbers(A,X,Y) {
|
|
%asm {{
|
|
ldy cx16.r0
|
|
sty P8ZP_SCRATCH_W1
|
|
ldy cx16.r0+1
|
|
sty P8ZP_SCRATCH_W1+1
|
|
ldx cx16.r1
|
|
ldy cx16.r1+1
|
|
jmp prog8_lib.memset
|
|
}}
|
|
}
|
|
|
|
asmsub memsetw(uword mem @R0, uword numwords @R1, uword value @AY) clobbers(A,X,Y) {
|
|
%asm {{
|
|
ldx cx16.r0
|
|
stx P8ZP_SCRATCH_W1
|
|
ldx cx16.r0+1
|
|
stx P8ZP_SCRATCH_W1+1
|
|
ldx cx16.r1
|
|
stx P8ZP_SCRATCH_W2
|
|
ldx cx16.r1+1
|
|
stx P8ZP_SCRATCH_W2+1
|
|
jmp prog8_lib.memsetw
|
|
}}
|
|
}
|
|
|
|
asmsub memcmp(uword address1 @R0, uword address2 @R1, uword size @AY) -> byte @A {
|
|
; Compares two blocks of memory
|
|
; Returns -1 (255), 0 or 1, meaning: block 1 sorts before, equal or after block 2.
|
|
%asm {{
|
|
sta P8ZP_SCRATCH_REG ; lsb(size)
|
|
sty P8ZP_SCRATCH_B1 ; msb(size)
|
|
lda cx16.r0
|
|
ldy cx16.r0+1
|
|
sta P8ZP_SCRATCH_W1
|
|
sty P8ZP_SCRATCH_W1+1
|
|
lda cx16.r1
|
|
ldy cx16.r1+1
|
|
sta P8ZP_SCRATCH_W2
|
|
sty P8ZP_SCRATCH_W2+1
|
|
|
|
ldx P8ZP_SCRATCH_B1
|
|
beq _no_msb_size
|
|
|
|
_loop_msb_size
|
|
ldy #0
|
|
- lda (P8ZP_SCRATCH_W1),y
|
|
cmp (P8ZP_SCRATCH_W2),y
|
|
bcs +
|
|
lda #-1
|
|
rts
|
|
+ beq +
|
|
lda #1
|
|
rts
|
|
+ iny
|
|
bne -
|
|
inc P8ZP_SCRATCH_W1+1
|
|
inc P8ZP_SCRATCH_W2+1
|
|
dec P8ZP_SCRATCH_B1 ; msb(size) -= 1
|
|
dex
|
|
bne _loop_msb_size
|
|
|
|
_no_msb_size
|
|
lda P8ZP_SCRATCH_REG ; lsb(size)
|
|
bne +
|
|
rts
|
|
|
|
+ ldy #0
|
|
- lda (P8ZP_SCRATCH_W1),y
|
|
cmp (P8ZP_SCRATCH_W2),y
|
|
bcs +
|
|
lda #-1
|
|
rts
|
|
+ beq +
|
|
lda #1
|
|
rts
|
|
+ iny
|
|
cpy P8ZP_SCRATCH_REG ; lsb(size)
|
|
bne -
|
|
|
|
lda #0
|
|
rts
|
|
}}
|
|
}
|
|
|
|
inline asmsub read_flags() -> ubyte @A {
|
|
%asm {{
|
|
php
|
|
pla
|
|
}}
|
|
}
|
|
|
|
inline asmsub clear_carry() {
|
|
%asm {{
|
|
clc
|
|
}}
|
|
}
|
|
|
|
inline asmsub set_carry() {
|
|
%asm {{
|
|
sec
|
|
}}
|
|
}
|
|
|
|
inline asmsub clear_irqd() {
|
|
%asm {{
|
|
cli
|
|
}}
|
|
}
|
|
|
|
inline asmsub set_irqd() {
|
|
%asm {{
|
|
sei
|
|
}}
|
|
}
|
|
|
|
inline asmsub irqsafe_set_irqd() {
|
|
%asm {{
|
|
php
|
|
sei
|
|
}}
|
|
}
|
|
|
|
inline asmsub irqsafe_clear_irqd() {
|
|
%asm {{
|
|
plp
|
|
}}
|
|
}
|
|
|
|
sub disable_caseswitch() {
|
|
; PET doesn't have a key to swap case, so no-op
|
|
}
|
|
|
|
sub enable_caseswitch() {
|
|
; PET doesn't have a key to swap case, so no-op
|
|
}
|
|
|
|
asmsub save_prog8_internals() {
|
|
%asm {{
|
|
lda P8ZP_SCRATCH_B1
|
|
sta save_SCRATCH_ZPB1
|
|
lda P8ZP_SCRATCH_REG
|
|
sta save_SCRATCH_ZPREG
|
|
lda P8ZP_SCRATCH_W1
|
|
sta save_SCRATCH_ZPWORD1
|
|
lda P8ZP_SCRATCH_W1+1
|
|
sta save_SCRATCH_ZPWORD1+1
|
|
lda P8ZP_SCRATCH_W2
|
|
sta save_SCRATCH_ZPWORD2
|
|
lda P8ZP_SCRATCH_W2+1
|
|
sta save_SCRATCH_ZPWORD2+1
|
|
rts
|
|
save_SCRATCH_ZPB1 .byte 0
|
|
save_SCRATCH_ZPREG .byte 0
|
|
save_SCRATCH_ZPWORD1 .word 0
|
|
save_SCRATCH_ZPWORD2 .word 0
|
|
; !notreached!
|
|
}}
|
|
}
|
|
|
|
asmsub restore_prog8_internals() {
|
|
%asm {{
|
|
lda save_prog8_internals.save_SCRATCH_ZPB1
|
|
sta P8ZP_SCRATCH_B1
|
|
lda save_prog8_internals.save_SCRATCH_ZPREG
|
|
sta P8ZP_SCRATCH_REG
|
|
lda save_prog8_internals.save_SCRATCH_ZPWORD1
|
|
sta P8ZP_SCRATCH_W1
|
|
lda save_prog8_internals.save_SCRATCH_ZPWORD1+1
|
|
sta P8ZP_SCRATCH_W1+1
|
|
lda save_prog8_internals.save_SCRATCH_ZPWORD2
|
|
sta P8ZP_SCRATCH_W2
|
|
lda save_prog8_internals.save_SCRATCH_ZPWORD2+1
|
|
sta P8ZP_SCRATCH_W2+1
|
|
rts
|
|
}}
|
|
}
|
|
|
|
asmsub exit(ubyte returnvalue @A) {
|
|
; -- immediately exit the program with a return code in the A register
|
|
%asm {{
|
|
sta p8_sys_startup.cleanup_at_exit._exitcode
|
|
ldx prog8_lib.orig_stackpointer
|
|
txs
|
|
jmp p8_sys_startup.cleanup_at_exit
|
|
}}
|
|
}
|
|
|
|
asmsub exit2(ubyte resulta @A, ubyte resultx @X, ubyte resulty @Y) {
|
|
; -- immediately exit the program with result values in the A, X and Y registers.
|
|
%asm {{
|
|
sta p8_sys_startup.cleanup_at_exit._exitcode
|
|
stx p8_sys_startup.cleanup_at_exit._exitcodeX
|
|
sty p8_sys_startup.cleanup_at_exit._exitcodeY
|
|
ldx prog8_lib.orig_stackpointer
|
|
txs
|
|
jmp p8_sys_startup.cleanup_at_exit
|
|
}}
|
|
}
|
|
|
|
asmsub exit3(ubyte resulta @A, ubyte resultx @X, ubyte resulty @Y, bool carry @Pc) {
|
|
; -- immediately exit the program with result values in the A, X and Y registers, and the Carry flag in the status register.
|
|
%asm {{
|
|
sta p8_sys_startup.cleanup_at_exit._exitcode
|
|
lda #0
|
|
rol a
|
|
sta p8_sys_startup.cleanup_at_exit._exitcodeCarry
|
|
stx p8_sys_startup.cleanup_at_exit._exitcodeX
|
|
sty p8_sys_startup.cleanup_at_exit._exitcodeY
|
|
ldx prog8_lib.orig_stackpointer
|
|
txs
|
|
jmp p8_sys_startup.cleanup_at_exit
|
|
}}
|
|
}
|
|
|
|
inline asmsub progend() -> uword @AY {
|
|
%asm {{
|
|
lda #<prog8_program_end
|
|
ldy #>prog8_program_end
|
|
}}
|
|
}
|
|
|
|
inline asmsub progstart() -> uword @AY {
|
|
%asm {{
|
|
lda #<prog8_program_start
|
|
ldy #>prog8_program_start
|
|
}}
|
|
}
|
|
|
|
inline asmsub push(ubyte value @A) {
|
|
%asm {{
|
|
pha
|
|
}}
|
|
}
|
|
|
|
inline asmsub pushw(uword value @AY) {
|
|
%asm {{
|
|
pha
|
|
tya
|
|
pha
|
|
}}
|
|
}
|
|
|
|
inline asmsub pop() -> ubyte @A {
|
|
%asm {{
|
|
pla
|
|
}}
|
|
}
|
|
|
|
inline asmsub popw() -> uword @AY {
|
|
%asm {{
|
|
pla
|
|
tay
|
|
pla
|
|
}}
|
|
}
|
|
|
|
}
|
|
|
|
cx16 {
|
|
; the sixteen virtual 16-bit registers that the CX16 has defined in the zeropage
|
|
; they are simulated on the PET as well but their location in memory is different
|
|
; (because there's no room for them in the zeropage)
|
|
; we select the top page of RAM (assume 32Kb)
|
|
&uword r0 = $7fe0
|
|
&uword r1 = $7fe2
|
|
&uword r2 = $7fe4
|
|
&uword r3 = $7fe6
|
|
&uword r4 = $7fe8
|
|
&uword r5 = $7fea
|
|
&uword r6 = $7fec
|
|
&uword r7 = $7fee
|
|
&uword r8 = $7ff0
|
|
&uword r9 = $7ff2
|
|
&uword r10 = $7ff4
|
|
&uword r11 = $7ff6
|
|
&uword r12 = $7ff8
|
|
&uword r13 = $7ffa
|
|
&uword r14 = $7ffc
|
|
&uword r15 = $7ffe
|
|
|
|
&word r0s = $7fe0
|
|
&word r1s = $7fe2
|
|
&word r2s = $7fe4
|
|
&word r3s = $7fe6
|
|
&word r4s = $7fe8
|
|
&word r5s = $7fea
|
|
&word r6s = $7fec
|
|
&word r7s = $7fee
|
|
&word r8s = $7ff0
|
|
&word r9s = $7ff2
|
|
&word r10s = $7ff4
|
|
&word r11s = $7ff6
|
|
&word r12s = $7ff8
|
|
&word r13s = $7ffa
|
|
&word r14s = $7ffc
|
|
&word r15s = $7ffe
|
|
|
|
&ubyte r0L = $7fe0
|
|
&ubyte r1L = $7fe2
|
|
&ubyte r2L = $7fe4
|
|
&ubyte r3L = $7fe6
|
|
&ubyte r4L = $7fe8
|
|
&ubyte r5L = $7fea
|
|
&ubyte r6L = $7fec
|
|
&ubyte r7L = $7fee
|
|
&ubyte r8L = $7ff0
|
|
&ubyte r9L = $7ff2
|
|
&ubyte r10L = $7ff4
|
|
&ubyte r11L = $7ff6
|
|
&ubyte r12L = $7ff8
|
|
&ubyte r13L = $7ffa
|
|
&ubyte r14L = $7ffc
|
|
&ubyte r15L = $7ffe
|
|
|
|
&ubyte r0H = $7fe1
|
|
&ubyte r1H = $7fe3
|
|
&ubyte r2H = $7fe5
|
|
&ubyte r3H = $7fe7
|
|
&ubyte r4H = $7fe9
|
|
&ubyte r5H = $7feb
|
|
&ubyte r6H = $7fed
|
|
&ubyte r7H = $7fef
|
|
&ubyte r8H = $7ff1
|
|
&ubyte r9H = $7ff3
|
|
&ubyte r10H = $7ff5
|
|
&ubyte r11H = $7ff7
|
|
&ubyte r12H = $7ff9
|
|
&ubyte r13H = $7ffb
|
|
&ubyte r14H = $7ffd
|
|
&ubyte r15H = $7fff
|
|
|
|
&byte r0sL = $7fe0
|
|
&byte r1sL = $7fe2
|
|
&byte r2sL = $7fe4
|
|
&byte r3sL = $7fe6
|
|
&byte r4sL = $7fe8
|
|
&byte r5sL = $7fea
|
|
&byte r6sL = $7fec
|
|
&byte r7sL = $7fee
|
|
&byte r8sL = $7ff0
|
|
&byte r9sL = $7ff2
|
|
&byte r10sL = $7ff4
|
|
&byte r11sL = $7ff6
|
|
&byte r12sL = $7ff8
|
|
&byte r13sL = $7ffa
|
|
&byte r14sL = $7ffc
|
|
&byte r15sL = $7ffe
|
|
|
|
&byte r0sH = $7fe1
|
|
&byte r1sH = $7fe3
|
|
&byte r2sH = $7fe5
|
|
&byte r3sH = $7fe7
|
|
&byte r4sH = $7fe9
|
|
&byte r5sH = $7feb
|
|
&byte r6sH = $7fed
|
|
&byte r7sH = $7fef
|
|
&byte r8sH = $7ff1
|
|
&byte r9sH = $7ff3
|
|
&byte r10sH = $7ff5
|
|
&byte r11sH = $7ff7
|
|
&byte r12sH = $7ff9
|
|
&byte r13sH = $7ffb
|
|
&byte r14sH = $7ffd
|
|
&byte r15sH = $7fff
|
|
|
|
asmsub save_virtual_registers() clobbers(A,Y) {
|
|
%asm {{
|
|
ldy #31
|
|
- lda cx16.r0,y
|
|
sta _cx16_vreg_storage,y
|
|
dey
|
|
bpl -
|
|
rts
|
|
|
|
_cx16_vreg_storage
|
|
.word 0,0,0,0,0,0,0,0
|
|
.word 0,0,0,0,0,0,0,0
|
|
; !notreached!
|
|
}}
|
|
}
|
|
|
|
asmsub restore_virtual_registers() clobbers(A,Y) {
|
|
%asm {{
|
|
ldy #31
|
|
- lda save_virtual_registers._cx16_vreg_storage,y
|
|
sta cx16.r0,y
|
|
dey
|
|
bpl -
|
|
rts
|
|
}}
|
|
}
|
|
|
|
sub cpu_is_65816() -> bool {
|
|
; Returns true when you have a 65816 cpu, false when it's a 6502.
|
|
return false
|
|
}
|
|
|
|
}
|
|
|
|
p8_sys_startup {
|
|
; program startup and shutdown machinery. Needs to reside in normal system ram.
|
|
|
|
asmsub init_system() {
|
|
; Initializes the machine to a sane starting state.
|
|
; Called automatically by the loader program logic.
|
|
; Uppercase charset is activated.
|
|
%asm {{
|
|
sei
|
|
lda #142
|
|
jsr cbm.CHROUT ; uppercase
|
|
lda #147
|
|
jsr cbm.CHROUT ; clear screen
|
|
cli
|
|
rts
|
|
}}
|
|
}
|
|
|
|
asmsub init_system_phase2() {
|
|
%asm {{
|
|
cld
|
|
clc
|
|
clv
|
|
rts
|
|
}}
|
|
}
|
|
|
|
asmsub cleanup_at_exit() {
|
|
; executed when the main subroutine does rts
|
|
%asm {{
|
|
_exitcodeCarry = *+1
|
|
lda #0
|
|
lsr a
|
|
_exitcode = *+1
|
|
lda #0 ; exit code possibly modified in exit()
|
|
_exitcodeX = *+1
|
|
ldx #0
|
|
_exitcodeY = *+1
|
|
ldy #0
|
|
rts
|
|
}}
|
|
}
|
|
|
|
}
|