61 lines
1.3 KiB
NASM
61 lines
1.3 KiB
NASM
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; framebuffer vfs stream routines
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framebuffer_vfs_stream_name: data.strz "fb"
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; open a framebuffer stream
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; inputs:
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; r2: file struct: pointer to a blank file struct (stream)
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; outputs:
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; r0: non-zero
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open_stream_fb:
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push r2
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mov.8 [r2], 0 ; write file_reserved_1
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inc r2
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mov.16 [r2], 0 ; write file_reserved_2
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add r2, 2
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mov [r2], 0 ; write file_seek_offset
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add r2, 4
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mov.8 [r2], 1 ; write file_system_type
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inc r2
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mov [r2], fb_stream_read ; write file_read_call
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add r2, 4
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mov [r2], fb_stream_write ; write file_write_call
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add r2, 4
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mov [r2], 0x0012C000 ; write file_size
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add r2, 4
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mov [r2], 0 ; write file_reserved_3
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add r2, 4
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mov [r2], 0 ; write file_reserved_4
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add r2, 4
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mov [r2], 0 ; write file_reserved_5
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pop r2
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mov r0, 1
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ret
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; read a byte from the framebuffer
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; inputs:
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; r0: seek offset
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; outputs:
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; r0: byte
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fb_stream_read:
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add r0, 0x02000000
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cmp r0, 0x0212C000
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ifgteq mov r0, 0x0212BFFF
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movz.8 r0, [r0]
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ret
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; write a byte to the framebuffer
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; inputs:
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; r0: pointer to source buffer
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; r1: seek offset
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; outputs:
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; none
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fb_stream_write:
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add r1, 0x02000000
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cmp r1, 0x0212C000
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ifgteq mov r1, 0x0212BFFF
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mov.8 [r1], [r0]
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ret
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