6502-OS/spicode.s65
2023-12-10 12:10:55 +01:00

200 lines
4.4 KiB
Plaintext

.include "system.h65"
.include "lcd.h65"
.include "math.h65"
.include "keypad.h65"
.import home:absolute
.segment "SPI"
.export CODE_START
CODE_START:
.assert * = $5000, error, "SPI Code not at $5000"
lda '$'
jsr lcd::print_char
lda #<TEST_FMT
sta ARG0
lda #>TEST_FMT
sta ARG1
lda #<TEST_OUT
sta ARG2
lda #>TEST_OUT
sta ARG3
lda #$a9
sta ARG4
lda #$3c
sta ARG5
lda #$10
sta ARG6
jsr strf
Print TEST_OUT
stz kp::_DEBUG_VAL
@loop:
lda kp::_DEBUG_VAL
jeq home
bra @loop
fmt_idx = $30
out_idx = $31
fmt_digit = $32
.proc strf
stz out_idx
stz fmt_idx
stz fmt_digit
ldx #0 ; index of format args
@loop:
ldy fmt_idx
lda (ARG0),y
beq @null
cmp #'%'
beq @percent
@normal_char: ; store A in output string
ldy out_idx
sta (ARG2),y
inc fmt_idx
inc out_idx
beq @out_overflow
bra @loop
@percent: ; check for format in next position
iny
sty fmt_idx
lda (ARG0),y ; next char
beq @null
; formats
cmp #'9'
ble @percent_number ; numbers < letters
cmp #'x'
beq @format_hex1
bra @normal_char
@percent_number:
cmp #'1'
blt @normal_char ; NaN or zero
; todo covert from char
jsr hex_char_to_int ; only 0-9 supported
; A is now number of digits to convert
sta fmt_digit
iny
sty fmt_idx
lda (ARG0),y ; next char
beq @null
cmp #'x'
beq @format_hexN
bra @normal_char
@format_hexN:
lda fmt_digit
jsr int_to_hex_str
bra @format_return
@format_hex1: ; 1 byte hex -> 2 chars
lda ARG4,x
phx
jsr int8_to_hex_str
ldy out_idx
sta (ARG2),y ; most sig digit
iny
beq @out_overflow
txa
sta (ARG2),y ; least sig digit
iny
beq @out_overflow
sty out_idx
plx
inx ; 1 byte of args handeled
; bra @format_return
@format_return: ; increment fmt_idx to swallow the formating char
inc fmt_idx
bra @loop
@out_overflow: ; store 0 in last position
ldy #$ff
sty out_idx
@store_null:
lda #0
@null: ; store and return
ldy out_idx
sta (ARG2),y
@rts:
rts
.endproc
;********************************************************************************
; @function Convert a 1 byte number into two hex characters
; @param A: Number to convert
; @returns A: Most significant digit
; @returns X: Least significant digit
; @modifies A,X,Y
;********************************************************************************
.proc int8_to_hex_str
pha
and #%00001111
tay
ldx HEX_CHARS_UPPER,y
pla
div A,16
and #%00001111
tay
lda HEX_CHARS_UPPER,y
rts
.endproc
; todo error handling
.proc hex_char_to_int
cmp #'A'
bge @char
sbc #'0'
rts
@char:
sbc #('A' - $A)
rts
.endproc
;********************************************************************************
; @function Convert any int into hex
; @param ARG2-3: Address of output string
; @param Y: Offset onto output string
; @param A: Number of digits to convert
; @param X: Offset onto ARG4 = start of int (big endian)
; @returns Y: New offset onto output string
; @returns A: 0
; @returns X: Offset onto ARG4 = past the end of number
; @modifies X,Y,A
;********************************************************************************
.proc int_to_hex_str
cmp #0
@loop:
beq @rts ; check done
; load next byte
pha
lda ARG4,x
inx
phx
pha ; copy byte
div A,16 ; get first 4 bits = first digit
and #%00001111
phy
tay
lda HEX_CHARS_LOWER,y
ply
sta (ARG2),y
iny
pla ; get copy
and #%00001111 ; lower 4 bits = second digit
phy
tay
lda HEX_CHARS_LOWER,y
ply
sta (ARG2),y
iny
plx
pla
dec
@rts:
rts
.endproc
TEST_FMT: .asciiz "%x -> %x -> %x:)"
TEST_OUT: .asciiz "TESTOUT"
HEX_CHARS_UPPER: .byte "0123456789ABCDEF"
HEX_CHARS_LOWER: .byte "0123456789abcdef"