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68a3b34374
prog8/lib/c64lib.ill
Irmen de Jong 68a3b34374 fix 16 bit inc dec
2017-12-29 01:16:39 +01:00

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; IL65 definitions for the Commodore-64
; Including memory registers, I/O registers, Basic and Kernel subroutines, utility subroutines.
;
; Written by Irmen de Jong (irmen@razorvine.net)
; License: GNU GPL 3.0, see LICENSE
;
; indent format: TABS, size=8
output raw
~ c64 {
memory SCRATCH_ZP1 = $02 ; scratch register #1 in ZP
memory SCRATCH_ZP2 = $03 ; scratch register #2 in ZP
memory .byte COLOR = $0286 ; cursor color
memory .word CINV = $0314 ; IRQ vector
; ---- VIC-II registers ----
memory SP0X = $d000
memory SP0Y = $d001
memory SP1X = $d002
memory SP1Y = $d003
memory SP2X = $d004
memory SP2Y = $d005
memory SP3X = $d006
memory SP3Y = $d007
memory SP4X = $d008
memory SP4Y = $d009
memory SP5X = $d00a
memory SP5Y = $d00b
memory SP6X = $d00c
memory SP6Y = $d00d
memory SP7X = $d00e
memory SP7Y = $d00f
memory MSIGX = $d010
memory SCROLY = $d011
memory RASTER = $d012
memory LPENX = $d013
memory LPENY = $d014
memory SPENA = $d015
memory SCROLX = $d016
memory YXPAND = $d017
memory VMCSB = $d018
memory VICIRQ = $d019
memory IREQMASK = $d01a
memory SPBGPR = $d01b
memory SPMC = $d01c
memory XXPAND = $d01d
memory SPSPCL = $d01e
memory SPBGCL = $d01f
memory EXTCOL = $d020 ; border color
memory BGCOL0 = $d021 ; screen color
memory BGCOL1 = $d022
memory BGCOL2 = $d023
memory BGCOL4 = $d024
memory SPMC0 = $d025
memory SPMC1 = $d026
memory SP0COL = $d027
memory SP1COL = $d028
memory SP2COL = $d029
memory SP3COL = $d02a
memory SP4COL = $d02b
memory SP5COL = $d02c
memory SP6COL = $d02d
memory SP7COL = $d02e
; ---- end of VIC-II registers ----
; ---- C64 basic and kernal ROM float constants and functions ----
; note: the fac1 and fac2 are working registers and take 6 bytes each,
; floats in memory (and rom) are stored in 5-byte MFLPT packed format.
; constants in five-byte "mflpt" format in the BASIC ROM
memory .float FL_PIVAL = $aea8 ; 3.1415926...
memory .float FL_N32768 = $b1a5 ; -32768
memory .float FL_FONE = $b9bc ; 1
memory .float FL_SQRHLF = $b9d6 ; SQR(2) / 2
memory .float FL_SQRTWO = $b9db ; SQR(2)
memory .float FL_NEGHLF = $b9e0 ; -.5
memory .float FL_LOG2 = $b9e5 ; LOG(2)
memory .float FL_TENC = $baf9 ; 10
memory .float FL_NZMIL = $bdbd ; 1e9 (1 billion)
memory .float FL_FHALF = $bf11 ; .5
memory .float FL_LOGEB2 = $bfbf ; 1 / LOG(2)
memory .float FL_PIHALF = $e2e0 ; PI / 2
memory .float FL_TWOPI = $e2e5 ; 2 * PI
memory .float FL_FR4 = $e2ea ; .25
; note: fac1/2 might get clobbered even if not mentioned in the function's name.
; note: for subtraction and division, the left operand is in fac2, the right operand in fac1.
; checked functions below:
sub MOVFM (mflpt: AY) -> (A?, Y?) = $bba2 ; load mflpt value from memory in A/Y into fac1
sub FREADMEM () -> (A?, Y?) = $bba6 ; load mflpt value from memory in $22/$23 into fac1
sub CONUPK (mflpt: AY) -> (A?, Y?) = $ba8c ; load mflpt value from memory in A/Y into fac2
sub FAREADMEM () -> (A?, Y?) = $ba90 ; load mflpt value from memory in $22/$23 into fac2
sub MOVFA () -> (A?, X?) = $bbfc ; copy fac2 to fac1
sub MOVAF () -> (A?, X?) = $bc0c ; copy fac1 to fac2 (rounded)
sub MOVEF () -> (A?, X?) = $bc0f ; copy fac1 to fac2
sub FTOMEMXY (mflpt: XY) -> (A?, Y?) = $bbd4 ; store fac1 to memory X/Y as 5-byte mflpt
sub FTOSWORDYA () -> (Y, A, X?) = $b1aa ; fac1-> signed word in Y/A (might throw ILLEGAL QUANTITY)
; use c64util.FTOSWRDAY to get A/Y output (lo/hi switched to normal order)
sub GETADR () -> (Y, A, X?) = $b7f7 ; fac1 -> unsigned word in Y/A (might throw ILLEGAL QUANTITY)
; (result also in $14/15) use c64util.GETADRAY to get A/Y output (lo/hi switched to normal order)
sub QINT () -> (A?, X?, Y?) = $bc9b ; fac1 -> 4-byte signed integer in 98-101 ($62-$65), with the MSB FIRST.
sub AYINT () -> (A?, X?, Y?) = $b1bf ; fac1-> signed word in 100-101 ($64-$65) MSB FIRST. (might throw ILLEGAL QUANTITY)
sub GIVAYF (lo: Y, hi: A) -> (A?, X?, Y?) = $b391 ; signed word in Y/A -> float in fac1
; use c64util.GIVAYFAY to use A/Y input (lo/hi switched to normal order)
; there is also c64util.GIVUAYF - unsigned word in A/Y (lo/hi) to fac1
; there is also c64util.FREADS32 that reads from 98-101 ($62-$65) MSB FIRST
; there is also c64util.FREADUS32 that reads from 98-101 ($62-$65) MSB FIRST
; there is also c64util.FREADS24AXY that reads signed int24 into fac1 from A/X/Y (lo/mid/hi bytes)
sub FREADUY (ubyte: Y) -> (A?, X?, Y?) = $b3a2 ; 8 bit unsigned Y -> float in fac1
sub FREADSA (sbyte: A) -> (A?, X?, Y?) = $bc3c ; 8 bit signed A -> float in fac1
sub FREADSTR (len: A) -> (A?, X?, Y?) = $b7b5 ; str -> fac1, $22/23 must point to string, A=string length
sub FPRINTLN () -> (A?, X?, Y?) = $aabc ; print string of fac1, on one line (= with newline)
sub FOUT () -> (AY, X?) = $bddd ; fac1 -> string, address returned in AY ($0100)
sub FADDH () -> (A?, X?, Y?) = $b849 ; fac1 += 0.5, for rounding- call this before INT
sub MUL10 () -> (A?, X?, Y?) = $bae2 ; fac1 *= 10
sub DIV10 () -> (A?, X?, Y?) = $bafe ; fac1 /= 10 , CAUTION: result is always positive!
sub FCOMP (mflpt: AY) -> (A, X?, Y?) = $bc5b ; A = compare fac1 to mflpt in A/Y, 0=equal 1=fac1 is greater, 255=fac1 is less than
sub FADDT () -> (A?, X?, Y?) = $b86a ; fac1 += fac2
sub FADD (mflpt: AY) -> (A?, X?, Y?) = $b867 ; fac1 += mflpt value from A/Y
sub FSUBT () -> (A?, X?, Y?) = $b853 ; fac1 = fac2-fac1 mind the order of the operands
sub FSUB (mflpt: AY) -> (A?, X?, Y?) = $b850 ; fac1 = mflpt from A/Y - fac1
sub FMULTT () -> (A?, X?, Y?) = $ba2b ; fac1 *= fac2
sub FMULT (mflpt: AY) -> (A?, X?, Y?) = $ba28 ; fac1 *= mflpt value from A/Y
sub FDIVT () -> (A?, X?, Y?) = $bb12 ; fac1 = fac2/fac1 mind the order of the operands
sub FDIV (mflpt: AY) -> (A?, X?, Y?) = $bb0f ; fac1 = mflpt in A/Y / fac1
sub FPWRT () -> (A?, X?, Y?) = $bf7b ; fac1 = fac2 ** fac1
sub FPWR (mflpt: AY) -> (A?, X?, Y?) = $bf78 ; fac1 = fac2 ** mflpt from A/Y
sub NOTOP () -> (A?, X?, Y?) = $aed4 ; fac1 = NOT(fac1)
sub INT () -> (A?, X?, Y?) = $bccc ; INT() truncates, use FADDH first to round instead of trunc
sub LOG () -> (A?, X?, Y?) = $b9ea ; fac1 = LN(fac1) (natural log)
sub SGN () -> (A?, X?, Y?) = $bc39 ; fac1 = SGN(fac1), result of SIGN (-1, 0 or 1)
sub SIGN () -> (A) = $bc2b ; SIGN(fac1) to A, $ff, $0, $1 for negative, zero, positive
sub ABS () -> () = $bc58 ; fac1 = ABS(fac1)
sub SQR () -> (A?, X?, Y?) = $bf71 ; fac1 = SQRT(fac1)
sub EXP () -> (A?, X?, Y?) = $bfed ; fac1 = EXP(fac1) (e ** fac1)
sub NEGOP () -> (A?) = $bfb4 ; switch the sign of fac1
sub RND () -> (A?, X?, Y?) = $e097 ; fac1 = RND() (use RNDA instead)
sub RNDA (A) -> (A?, X?, Y?) = $e09a ; fac1 = RND(A)
sub COS () -> (A?, X?, Y?) = $e264 ; fac1 = COS(fac1)
sub SIN () -> (A?, X?, Y?) = $e26b ; fac1 = SIN(fac1)
sub TAN () -> (A?, X?, Y?) = $e2b4 ; fac1 = TAN(fac1)
sub ATN () -> (A?, X?, Y?) = $e30e ; fac1 = ATN(fac1)
; ---- C64 basic routines ----
sub CLEARSCR () -> (A?, X?, Y?) = $E544 ; clear the screen
sub HOMECRSR () -> (A?, X?, Y?) = $E566 ; cursor to top left of screen
; ---- end of C64 basic routines ----
; ---- C64 kernal routines ----
sub IRQDFRT () -> (A?, X?, Y?) = $EA31 ; default IRQ routine
sub IRQDFEND () -> (A?, X?, Y?) = $EA81 ; default IRQ end/cleanup
sub CINT () -> (A?, X?, Y?) = $FF81 ; (alias: SCINIT) initialize screen editor and video chip
sub IOINIT () -> (A?, X?) = $FF84 ; initialize I/O devices (CIA, SID, IRQ)
sub RAMTAS () -> (A?, X?, Y?) = $FF87 ; initialize RAM, tape buffer, screen
sub RESTOR () -> (A?, X?, Y?) = $FF8A ; restore default I/O vectors
sub VECTOR (dir: SC, userptr: XY) -> (A?, Y?) = $FF8D ; read/set I/O vector table
sub SETMSG (value: A) -> () = $FF90 ; set Kernal message control flag
sub SECOND (address: A) -> (A?) = $FF93 ; (alias: LSTNSA) send secondary address after LISTEN
sub TKSA (address: A) -> (A?) = $FF96 ; (alias: TALKSA) send secondary address after TALK
sub MEMTOP (dir: SC, address: XY) -> (XY) = $FF99 ; read/set top of memory pointer
sub MEMBOT (dir: SC, address: XY) -> (XY) = $FF9C ; read/set bottom of memory pointer
sub SCNKEY () -> (A?, X?, Y?) = $FF9F ; scan the keyboard
sub SETTMO (timeout: A) -> () = $FFA2 ; set time-out flag for IEEE bus
sub ACPTR () -> (A) = $FFA5 ; (alias: IECIN) input byte from serial bus
sub CIOUT (byte: A) -> () = $FFA8 ; (alias: IECOUT) output byte to serial bus
sub UNTLK () -> (A?) = $FFAB ; command serial bus device to UNTALK
sub UNLSN () -> (A?) = $FFAE ; command serial bus device to UNLISTEN
sub LISTEN (device: A) -> (A?) = $FFB1 ; command serial bus device to LISTEN
sub TALK (device: A) -> (A?) = $FFB4 ; command serial bus device to TALK
sub READST () -> (A) = $FFB7 ; read I/O status word
sub SETLFS (logical: A, device: X, address: Y) -> () = $FFBA ; set logical file parameters
sub SETNAM (namelen: A, filename: XY) -> () = $FFBD ; set filename parameters
sub OPEN () -> (A?, X?, Y?) = $FFC0 ; (via 794 ($31A)) open a logical file
sub CLOSE (logical: A) -> (A?, X?, Y?) = $FFC3 ; (via 796 ($31C)) close a logical file
sub CHKIN (logical: X) -> (A?, X?) = $FFC6 ; (via 798 ($31E)) define an input channel
sub CHKOUT (logical: X) -> (A?, X?) = $FFC9 ; (via 800 ($320)) define an output channel
sub CLRCHN () -> (A?, X?) = $FFCC ; (via 802 ($322)) restore default devices
sub CHRIN () -> (A, Y?) = $FFCF ; (via 804 ($324)) input a character (for keyboard, read a whole line from the screen) A=byte read.
sub CHROUT (char: A) -> () = $FFD2 ; (via 806 ($326)) output a character
sub LOAD (verify: A, address: XY) -> (SC, A, X, Y) = $FFD5 ; (via 816 ($330)) load from device
sub SAVE (zp_startaddr: A, endaddr: XY) -> (SC, A) = $FFD8 ; (via 818 ($332)) save to a device
sub SETTIM (low: A, middle: X, high: Y) -> () = $FFDB ; set the software clock
sub RDTIM () -> (A, X, Y) = $FFDE ; read the software clock
sub STOP () -> (SZ, SC, A?, X?) = $FFE1 ; (via 808 ($328)) check the STOP key
sub GETIN () -> (A, X?, Y?) = $FFE4 ; (via 810 ($32A)) get a character
sub CLALL () -> (A?, X?) = $FFE7 ; (via 812 ($32C)) close all files
sub UDTIM () -> (A?, X?) = $FFEA ; update the software clock
sub SCREEN () -> (X, Y) = $FFED ; read number of screen rows and columns
sub PLOT (dir: SC, col: X, row: Y) -> (X, Y) = $FFF0 ; read/set position of cursor on screen
sub IOBASE () -> (X, Y) = $FFF3 ; read base address of I/O devices
; ---- end of C64 kernal routines ----
memory .word NMI_VEC = $FFFA ; nmi vector, set by the kernal if banked in
memory .word RESET_VEC = $FFFC ; reset vector, set by the kernal if banked in
memory .word IRQ_VEC = $FFFE ; interrupt vector, set by the kernal if banked in
}
~ c64util {
sub init_system () -> (A?, X?, Y?) {
; ---- initializes the machine to a sane starting state
; This means that the BASIC, KERNAL and CHARGEN ROMs are banked in,
; the VIC, SID and CIA chips are reset, screen is cleared, and the default IRQ is set.
; Also a different color scheme is chosen to identify ourselves a little.
asm {
sei
cld
lda #%00101111
sta $00
lda #%00100111
sta $01
jsr c64.IOINIT
jsr c64.RESTOR
jsr c64.CINT
lda #6
sta c64.EXTCOL
lda #7
sta c64.COLOR
lda #0
sta c64.BGCOL0
tax
tay
clc
clv
cli
rts
}
}
sub FREADS32 () -> (A?, X?, Y?) {
; ---- fac1 = signed int32 from $62-$65 big endian (MSB FIRST)
asm {
lda $62
eor #$ff
asl a
lda #0
ldx #$a0
jmp $bc4f ; internal BASIC routine
}
}
sub FREADUS32 () -> (A?, X?, Y?) {
; ---- fac1 = uint32 from $62-$65 big endian (MSB FIRST)
asm {
sec
lda #0
ldx #$a0
jmp $bc4f ; internal BASIC routine
}
}
sub FREADS24AXY (lo: A, mid: X, hi: Y) -> (A?, X?, Y?) {
; ---- fac1 = signed int24 (A/X/Y contain lo/mid/hi bytes)
; note: there is no FREADU24AXY (unsigned), use FREADUS32 instead.
asm {
sty $62
stx $63
sta $64
lda $62
eor #$FF
asl a
lda #0
sta $65
ldx #$98
jmp $bc4f ; internal BASIC routine
}
}
sub GIVUAYF (uword: AY) -> (A?, X?, Y?) {
; ---- unsigned 16 bit word in A/Y (lo/hi) to fac1
asm {
sty $62
sta $63
ldx #$90
sec
jmp $bc49 ; internal BASIC routine
}
}
sub GIVAYFAY (sword: AY) -> (A?, X?, Y?) {
; ---- signed 16 bit word in A/Y (lo/hi) to float in fac1
asm {
sta c64.SCRATCH_ZP1
tya
ldy c64.SCRATCH_ZP1
jmp c64.GIVAYF ; this uses the inverse order, Y/A
}
}
sub FTOSWRDAY () -> (AY, X?) {
; ---- fac1 to signed word in A/Y
asm {
jsr c64.FTOSWORDYA ; note the inverse Y/A order
sta c64.SCRATCH_ZP1
tya
ldy c64.SCRATCH_ZP1
rts
}
}
sub GETADRAY () -> (AY, X?) {
; ---- fac1 to unsigned word in A/Y
asm {
jsr c64.GETADR ; this uses the inverse order, Y/A
sta c64.SCRATCH_ZP1
tya
ldy c64.SCRATCH_ZP1
rts
}
}
; @todo optimize print_string()/ print_pstring() of a single character into a call to c64.CHROUT instead
sub print_string (address: XY) -> (A?, Y?) {
; ---- print null terminated string from X/Y
asm {
stx c64.SCRATCH_ZP1
sty c64.SCRATCH_ZP2
ldy #0
- lda (c64.SCRATCH_ZP1),y
beq +
jsr c64.CHROUT
iny
bne -
+ rts
}
}
sub print_pstring (address: XY) -> (A?, X?, Y) {
; ---- print pstring (length as first byte) from X/Y, returns str len in Y
asm {
stx c64.SCRATCH_ZP1
sty c64.SCRATCH_ZP2
ldy #0
lda (c64.SCRATCH_ZP1),y
beq +
tax
- iny
lda (c64.SCRATCH_ZP1),y
jsr c64.CHROUT
dex
bne -
+ rts ; output string length is in Y
}
}
sub print_pimmediate () -> () {
; ---- print pstring in memory immediately following the subroutine fast call instruction
; note that the clobbered registers (A,X,Y) are not listed ON PURPOSE
asm {
tsx
lda $102,x
tay ; put high byte in y
lda $101,x
tax ; and low byte in x.
inx
bne +
iny
+ jsr print_pstring ; print string in XY, returns string length in y.
tya
tsx
clc
adc $101,x ; add content of 1st (length) byte to return addr.
bcc + ; if that made the low byte roll over to 00,
inc $102,x ; then increment the high byte too.
+ clc
adc #1 ; now add 1 for the length byte itself.
sta $101,x
bne + ; if that made it (the low byte) roll over to 00,
inc $102,x ; increment the high byte of the return addr too.
+ rts
}
}
sub byte2decimal (ubyte: A) -> (Y, X, A) {
; ---- A to decimal string in Y/X/A (100s in Y, 10s in X, 1s in A)
asm {
ldy #$2f
ldx #$3a
sec
- iny
sbc #100
bcs -
- dex
adc #10
bmi -
adc #$2f
rts
}
}
sub byte2hex (ubyte: A) -> (X, Y, A?) {
; ---- A to hex string in XY (first hex char in X, second hex char in Y)
asm {
pha
and #$0f
tax
ldy hex_digits,x
pla
lsr a
lsr a
lsr a
lsr a
tax
lda hex_digits,x
tax
rts
hex_digits .text "0123456789abcdef" ; can probably be reused for other stuff as well
}
}
var .array(3) word2bcd_bcdbuff
sub word2bcd (address: XY) -> (A?, X?) {
; Convert an 16 bit binary value to BCD
;
; This function converts a 16 bit binary value in X/Y into a 24 bit BCD. It
; works by transferring one bit a time from the source and adding it
; into a BCD value that is being doubled on each iteration. As all the
; arithmetic is being done in BCD the result is a binary to decimal
; conversion.
asm {
stx c64.SCRATCH_ZP1
sty c64.SCRATCH_ZP2
sed ; switch to decimal mode
lda #0 ; ensure the result is clear
sta word2bcd_bcdbuff+0
sta word2bcd_bcdbuff+1
sta word2bcd_bcdbuff+2
ldx #16 ; the number of source bits
- asl c64.SCRATCH_ZP1 ; shift out one bit
rol c64.SCRATCH_ZP2
lda word2bcd_bcdbuff+0 ; and add into result
adc word2bcd_bcdbuff+0
sta word2bcd_bcdbuff+0
lda word2bcd_bcdbuff+1 ; propagating any carry
adc word2bcd_bcdbuff+1
sta word2bcd_bcdbuff+1
lda word2bcd_bcdbuff+2 ; ... thru whole result
adc word2bcd_bcdbuff+2
sta word2bcd_bcdbuff+2
dex ; and repeat for next bit
bne -
cld ; back to binary
rts
}
}
var .array(5) word2decimal_output
sub word2decimal (address: XY) -> (A?, X?, Y?) {
; ---- convert 16 bit word in X/Y into decimal string into memory 'word2decimal_output'
asm {
jsr word2bcd
lda word2bcd_bcdbuff+2
clc
adc #'0'
sta word2decimal_output
ldy #1
lda word2bcd_bcdbuff+1
jsr +
lda word2bcd_bcdbuff+0
+ pha
lsr a
lsr a
lsr a
lsr a
clc
adc #'0'
sta word2decimal_output,y
iny
pla
and #$0f
adc #'0'
sta word2decimal_output,y
iny
rts
}
}
sub print_byte_decimal0 (ubyte: A) -> (A?, X?, Y?) {
; ---- print the byte in A in decimal form, with left padding 0s (3 positions total)
asm {
jsr byte2decimal
pha
tya
jsr c64.CHROUT
txa
jsr c64.CHROUT
pla
jmp c64.CHROUT
}
}
sub print_byte_decimal (ubyte: A) -> (A?, X?, Y?) {
; ---- print the byte in A in decimal form, without left padding 0s
asm {
jsr byte2decimal
pha
tya
cmp #'0'
beq +
jsr c64.CHROUT
+ txa
cmp #'0'
beq +
jsr c64.CHROUT
+ pla
jmp c64.CHROUT
}
}
sub print_byte_hex (ubyte: A) -> (A?, X?, Y?) {
; ---- print the byte in A in hex form
asm {
jsr byte2hex
txa
jsr c64.CHROUT
tya
jmp c64.CHROUT
}
}
sub print_word_decimal0 (address: XY) -> (A?, X?, Y?) {
; ---- print the word in X/Y in decimal form, with left padding 0s (5 positions total)
asm {
jsr word2decimal
lda word2decimal_output
jsr c64.CHROUT
lda word2decimal_output+1
jsr c64.CHROUT
lda word2decimal_output+2
jsr c64.CHROUT
lda word2decimal_output+3
jsr c64.CHROUT
lda word2decimal_output+4
jmp c64.CHROUT
}
}
sub print_word_decimal (address: XY) -> (A?, X? Y?) {
; ---- print the word in X/Y in decimal form, without left padding 0s
asm {
jsr word2decimal
ldy #0
lda word2decimal_output
cmp #'0'
bne _pr_decimal
iny
lda word2decimal_output+1
cmp #'0'
bne _pr_decimal
iny
lda word2decimal_output+2
cmp #'0'
bne _pr_decimal
iny
lda word2decimal_output+3
cmp #'0'
bne _pr_decimal
iny
_pr_decimal
lda word2decimal_output,y
jsr c64.CHROUT
iny
cpy #5
bcc _pr_decimal
rts
}
}
; @todo string to 32 bit unsigned integer http://www.6502.org/source/strings/ascii-to-32bit.html
sub input_chars (buffer: AX) -> (A?, Y) {
; ---- Input a string (max. 80 chars) from the keyboard.
; It assumes the keyboard is selected as I/O channel!!
asm {
sta c64.SCRATCH_ZP1
stx c64.SCRATCH_ZP2
ldy #0 ; char counter = 0
- jsr c64.CHRIN
cmp #$0d ; return (ascii 13) pressed?
beq + ; yes, end.
sta (c64.SCRATCH_ZP1),y ; else store char in buffer
iny
bne -
+ lda #0
sta (c64.SCRATCH_ZP1),y ; finish string with 0 byte
rts
}
}
;sub memcopy_basic () -> (A?, X?, Y?) {
; ; ---- copy a memory block by using a BASIC ROM routine @todo fix code
; ; it calls a function from the basic interpreter, so:
; ; - BASIC ROM must be banked in
; ; - the source block must be readable (so no RAM hidden under BASIC, Kernal, or I/O)
; ; - the target block must be writable (so no RAM hidden under I/O)
; ; higher addresses are copied first, so:
; ; - moving data to higher addresses works even if areas overlap
; ; - moving data to lower addresses only works if areas do not overlap
; ; @todo fix this
; asm {
; lda #<src_start
; ldx #>src_start
; sta $5f
; stx $60
; lda #<src_end
; ldx #>src_end
; sta $5a
; stx $5b
; lda #<(target_start + src_end - src_start)
; ldx #>(target_start + src_end - src_start)
; sta $58
; stx $59
; jmp $a3bf
; }
;}
; macro version of the above memcopy_basic routine: @todo macro support?
; MACRO PARAMS src_start, src_end, target_start
; lda #<src_start
; ldx #>src_start
; sta $5f
; stx $60
; lda #<src_end
; ldx #>src_end
; sta $5a
; stx $5b
; lda #<(target_start + src_end - src_start)
; ldx #>(target_start + src_end - src_start)
; sta $58
; stx $59
; jsr $a3bf
}
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