343 lines
8.0 KiB
NASM
343 lines
8.0 KiB
NASM
; generic text drawing routines
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; draw a single font tile to a framebuffer
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; inputs:
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; r0: tile number
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; r1: X coordinate
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; r2: Y coordinate
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; r3: foreground color
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; r4: background color
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; r5: pointer to font graphics
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; r6: font width
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; r7: font height
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; r8: pointer to framebuffer
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; r9: framebuffer width (pixels)
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; outputs:
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; none
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draw_font_tile_generic:
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push r0
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push r1
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push r2
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push r5
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push r6
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push r7
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push r8
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push r9
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;movz.8 r0, r0 ; ensure the tile number is a single byte
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; calculate pointer to the tile data
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push r6
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mul r6, r7
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mul r0, r6
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mul r0, 4 ; 4 bytes per pixel
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add r0, r5 ; r0: pointer to tile data
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pop r6
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; calculate pointer to the framebuffer
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mul r9, 4 ; 4 bytes per pixel
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mul r2, r9 ; y * width * 4
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mul r1, 4 ; x * 4
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add r1, r2 ; y * width * 4 + (x * 4)
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add r1, r8 ; r1: pointer to framebuffer
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; r8: font width in bytes
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mov r8, r6
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mul r8, 4
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draw_font_tile_generic_y_loop:
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mov r5, r6 ; x counter
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draw_font_tile_generic_x_loop:
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mov r2, [r0]
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cmp r2, 0xFF000000
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ifz jmp draw_font_tile_generic_x_loop_background
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; drawing foreground pixel
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cmp r3, 0x00000000 ; is the foreground color supposed to be transparent?
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ifz jmp draw_font_tile_generic_x_loop_end
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mov [r1], r3 ; draw foreground color
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jmp draw_font_tile_generic_x_loop_end
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draw_font_tile_generic_x_loop_background:
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; drawing background pixel
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cmp r4, 0x00000000 ; is the background color supposed to be transparent?
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ifz jmp draw_font_tile_generic_x_loop_end
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mov [r1], r4 ; draw background color
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draw_font_tile_generic_x_loop_end:
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add r0, 4 ; increment tile pointer
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add r1, 4 ; increment framebuffer pointer
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dec r5
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ifnz jmp draw_font_tile_generic_x_loop ; loop if there are still more X pixels to draw
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sub r1, r8 ; return to the beginning of this line
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add r1, r9 ; increment to the next line by adding the framebuffer width in bytes
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dec r7 ; decrement height counter
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ifnz jmp draw_font_tile_generic_y_loop ; loop if there are still more Y pixels to draw
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pop r9
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pop r8
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pop r7
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pop r6
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pop r5
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pop r2
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pop r1
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pop r0
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ret
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; draw text to a framebuffer, using printf-style formatting
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; inputs:
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; r0: pointer to null-terminated string
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; r1: X coordinate
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; r2: Y coordinate
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; r3: foreground color
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; r4: background color
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; r5: pointer to font graphics
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; r6: font width
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; r7: font height
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; r8: pointer to framebuffer
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; r9: framebuffer width
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; r10-r15: optional format values
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; outputs:
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; r1: X coordinate of end of text
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draw_format_str_generic:
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push r0
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push r1
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push r2
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push r5
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push r6
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push r7
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push r8
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push r9
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push r16
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push r17
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mov r16, 0 ; current format specifier counter
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draw_format_str_generic_loop:
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cmp.8 [r0], 0
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ifz jmp draw_format_str_generic_end
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cmp.8 [r0], '%'
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ifz jmp draw_format_str_generic_found_format_specifier
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; if this is not a format specifier or the end of the string, print the character
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push r0
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movz.8 r0, [r0]
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call draw_font_tile_generic
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pop r0
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add r1, r6 ; add the font width to the X coordinate
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inc r0
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jmp draw_format_str_generic_loop
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draw_format_str_generic_found_format_specifier:
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inc r0
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; percent sign
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cmp.8 [r0], '%'
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ifz call draw_format_str_generic_percent_sign
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; character
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cmp.8 [r0], 'c'
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ifz call draw_format_str_generic_character
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; unsigned decimal
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cmp.8 [r0], 'u'
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ifz call draw_format_str_generic_unsigned_decimal
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; hex
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cmp.8 [r0], 'x'
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ifz call draw_format_str_generic_hex
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inc r0
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jmp draw_format_str_generic_loop
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draw_format_str_generic_percent_sign:
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push r0
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mov r0, '%'
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call draw_font_tile_generic
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add r1, r6
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pop r0
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inc r16
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ret
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draw_format_str_generic_character:
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call draw_format_str_generic_get_parameter
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push r0
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mov r0, r17
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call draw_font_tile_generic
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add r1, r6
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pop r0
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inc r16
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ret
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draw_format_str_generic_unsigned_decimal:
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call draw_format_str_generic_get_parameter
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push r0
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mov r0, r17
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call draw_decimal_generic
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pop r0
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inc r16
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ret
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draw_format_str_generic_hex:
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call draw_format_str_generic_get_parameter
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push r0
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mov r0, r17
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call draw_hex_generic
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pop r0
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inc r16
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ret
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draw_format_str_generic_get_parameter:
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; load the correct format parameter into r17
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; this is messy, but i don't know of any other way to do this at the moment
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cmp r16, 0
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ifz jmp draw_format_str_generic_get_parameter_0
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cmp r16, 1
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ifz jmp draw_format_str_generic_get_parameter_1
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cmp r16, 2
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ifz jmp draw_format_str_generic_get_parameter_2
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cmp r16, 3
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ifz jmp draw_format_str_generic_get_parameter_3
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cmp r16, 4
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ifz jmp draw_format_str_generic_get_parameter_4
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cmp r16, 5
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ifz jmp draw_format_str_generic_get_parameter_5
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mov r17, 0
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ret
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draw_format_str_generic_get_parameter_0:
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mov r17, r10
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ret
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draw_format_str_generic_get_parameter_1:
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mov r17, r11
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ret
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draw_format_str_generic_get_parameter_2:
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mov r17, r12
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ret
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draw_format_str_generic_get_parameter_3:
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mov r17, r13
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ret
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draw_format_str_generic_get_parameter_4:
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mov r17, r14
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ret
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draw_format_str_generic_get_parameter_5:
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mov r17, r15
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ret
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draw_format_str_generic_end:
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pop r17
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pop r16
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pop r9
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pop r8
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pop r7
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pop r6
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pop r5
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pop r2
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pop r1
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pop r0
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ret
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; draw text to a framebuffer
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; inputs:
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; r0: pointer to null-terminated string
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; r1: X coordinate
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; r2: Y coordinate
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; r3: foreground color
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; r4: background color
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; r5: pointer to font graphics
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; r6: font width
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; r7: font height
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; r8: pointer to framebuffer
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; r9: framebuffer width
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; outputs:
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; r1: X coordinate of end of text
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draw_str_generic:
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push r0
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push r10
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mov r10, r0
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draw_str_generic_loop:
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movz.8 r0, [r10]
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call draw_font_tile_generic
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inc r10
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add r1, r6
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cmp.8 [r10], 0x00
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ifnz jmp draw_str_generic_loop
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pop r10
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pop r0
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ret
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; draw a decimal value to a framebuffer
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; inputs:
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; r0: value
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; r1: X coordinate
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; r2: Y coordinate
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; r3: foreground color
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; r4: background color
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; r5: pointer to font graphics
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; r6: font width
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; r7: font height
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; r8: pointer to framebuffer
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; r9: framebuffer width
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; outputs:
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; r1: X coordinate of end of text
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draw_decimal_generic:
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push r0
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push r10 ; r10: original stack pointer
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push r11 ; temp 1
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push r12 ; temp 2
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push r13 ; temp 3
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mov r10, rsp
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mov r12, r0
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push.8 0x00 ; end the string with a terminator
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draw_decimal_generic_find_loop:
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push r12
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div r12, 10 ; quotient goes into r12
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pop r13
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rem r13, 10 ; remainder goes into r13
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mov r11, r13
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add r11, '0'
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push.8 r11
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cmp r12, 0
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ifnz jmp draw_decimal_generic_find_loop
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draw_decimal_generic_print:
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mov r0, rsp ; point to start of string in the stack
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call draw_str_generic
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mov rsp, r10
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pop r13
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pop r12
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pop r11
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pop r10
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pop r0
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ret
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; draw a hex value to a framebuffer
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; inputs:
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; r0: value
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; r1: X coordinate
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; r2: Y coordinate
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; r3: foreground color
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; r4: background color
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; r5: pointer to font graphics
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; r6: font width
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; r7: font height
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; r8: pointer to framebuffer
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; r9: framebuffer width
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; outputs:
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; r1: X coordinate of end of text
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draw_hex_generic:
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push r10
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push r11
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push r12
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push r31
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mov r10, r0
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mov r31, 8
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draw_hex_generic_loop:
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rol r10, 4
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movz.16 r11, r10
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and r11, 0x0F
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mov r12, draw_hex_generic_characters
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add r12, r11
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movz.8 r0, [r12]
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call draw_font_tile_generic
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add r1, r6
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loop draw_hex_generic_loop
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pop r31
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pop r12
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pop r11
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pop r10
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ret
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draw_hex_generic_characters: data.str "0123456789ABCDEF"
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