mirror of https://gitlab.com/camelot/kickc.git
266 lines
5.0 KiB
NASM
266 lines
5.0 KiB
NASM
// Implementing a semi-struct without the struct keyword by using pointer math and inline functions
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//
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// struct Point {
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// byte xpos; // The x-position
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// byte ypos; // The y-position
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// };
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// Point points[NUM_POINTS];
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// Commodore 64 PRG executable file
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.file [name="semi-struct-1.prg", type="prg", segments="Program"]
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.segmentdef Program [segments="Basic, Code, Data"]
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.segmentdef Basic [start=$0801]
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.segmentdef Code [start=$80d]
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.segmentdef Data [startAfter="Code"]
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.segment Basic
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:BasicUpstart(main)
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// The size of a point
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.const SIZEOF_POINT = 2
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// The number of points
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.const NUM_POINTS = 4
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.label print_screen = $400
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.label print_line_cursor = 6
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.label print_char_cursor = 2
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.segment Code
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// Initialize some points and print them
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main: {
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// init_points()
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jsr init_points
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// print_points()
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jsr print_points
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// }
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rts
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}
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// Initialize points
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init_points: {
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.label getPoint1_return = 6
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.label pos = 8
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lda #$a
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sta.z pos
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ldx #0
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__b1:
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// idx*SIZEOF_POINT
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txa
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asl
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tay
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// points+idx*SIZEOF_POINT
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tya
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clc
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adc #<points
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sta.z getPoint1_return
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lda #>points
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adc #0
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sta.z getPoint1_return+1
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// *pointXpos(point) = pos
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lda.z pos
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sta points,y
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// pos +=10
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lda #$a
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clc
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adc.z pos
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// *pointYpos(point) = pos
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ldy #1
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sta (getPoint1_return),y
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// pos +=10
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clc
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adc #$a
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sta.z pos
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// for(byte i: 0..NUM_POINTS-1)
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inx
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cpx #NUM_POINTS-1+1
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bne __b1
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// }
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rts
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}
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// Print points
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print_points: {
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.label point = 9
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.label i = 8
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// print_cls()
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jsr print_cls
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lda #<print_screen
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sta.z print_line_cursor
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lda #>print_screen
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sta.z print_line_cursor+1
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lda #<print_screen
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sta.z print_char_cursor
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lda #>print_screen
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sta.z print_char_cursor+1
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lda #0
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sta.z i
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__b1:
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// idx*SIZEOF_POINT
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lda.z i
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asl
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tay
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// points+idx*SIZEOF_POINT
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tya
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clc
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adc #<points
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sta.z point
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lda #>points
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adc #0
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sta.z point+1
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// print_uchar(*pointXpos(point))
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ldx points,y
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jsr print_uchar
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// print_str(" ")
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jsr print_str
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// print_uchar(*pointYpos(point))
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ldy #1
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lda (point),y
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tax
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jsr print_uchar
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// print_ln()
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jsr print_ln
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// for(byte i: 0..NUM_POINTS-1)
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inc.z i
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lda #NUM_POINTS-1+1
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cmp.z i
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bne __b7
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// }
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rts
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__b7:
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lda.z print_line_cursor
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sta.z print_char_cursor
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lda.z print_line_cursor+1
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sta.z print_char_cursor+1
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jmp __b1
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.segment Data
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str: .text " "
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.byte 0
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}
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.segment Code
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// Clear the screen. Also resets current line/char cursor.
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print_cls: {
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// memset(print_screen, ' ', 1000)
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jsr memset
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// }
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rts
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}
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// Print a char as HEX
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// void print_uchar(__register(X) char b)
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print_uchar: {
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// b>>4
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txa
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lsr
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lsr
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lsr
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lsr
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// print_char(print_hextab[b>>4])
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tay
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lda print_hextab,y
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// Table of hexadecimal digits
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jsr print_char
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// b&0xf
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lda #$f
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axs #0
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// print_char(print_hextab[b&0xf])
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lda print_hextab,x
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jsr print_char
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// }
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rts
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}
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// Print a zero-terminated string
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// void print_str(__zp(4) char *str)
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print_str: {
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.label str = 4
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lda #<print_points.str
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sta.z str
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lda #>print_points.str
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sta.z str+1
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__b1:
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// while(*str)
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ldy #0
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lda (str),y
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cmp #0
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bne __b2
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// }
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rts
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__b2:
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// print_char(*(str++))
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ldy #0
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lda (str),y
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jsr print_char
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// print_char(*(str++));
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inc.z str
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bne !+
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inc.z str+1
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!:
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jmp __b1
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}
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// Print a newline
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print_ln: {
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__b1:
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// print_line_cursor + 0x28
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lda #$28
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clc
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adc.z print_line_cursor
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sta.z print_line_cursor
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bcc !+
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inc.z print_line_cursor+1
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!:
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// while (print_line_cursor<print_char_cursor)
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lda.z print_line_cursor+1
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cmp.z print_char_cursor+1
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bcc __b1
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bne !+
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lda.z print_line_cursor
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cmp.z print_char_cursor
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bcc __b1
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!:
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// }
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rts
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}
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// Copies the character c (an unsigned char) to the first num characters of the object pointed to by the argument str.
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// void * memset(void *str, char c, unsigned int num)
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memset: {
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.const c = ' '
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.const num = $3e8
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.label str = print_screen
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.label end = str+num
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.label dst = 4
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lda #<str
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sta.z dst
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lda #>str
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sta.z dst+1
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__b1:
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// for(char* dst = str; dst!=end; dst++)
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lda.z dst+1
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cmp #>end
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bne __b2
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lda.z dst
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cmp #<end
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bne __b2
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// }
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rts
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__b2:
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// *dst = c
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lda #c
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ldy #0
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sta (dst),y
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// for(char* dst = str; dst!=end; dst++)
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inc.z dst
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bne !+
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inc.z dst+1
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!:
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jmp __b1
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}
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// Print a single char
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// void print_char(__register(A) char ch)
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print_char: {
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// *(print_char_cursor++) = ch
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ldy #0
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sta (print_char_cursor),y
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// *(print_char_cursor++) = ch;
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inc.z print_char_cursor
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bne !+
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inc.z print_char_cursor+1
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!:
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// }
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rts
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}
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.segment Data
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print_hextab: .text "0123456789abcdef"
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// All points
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points: .fill NUM_POINTS*SIZEOF_POINT, 0
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