44 lines
578 B
NASM
44 lines
578 B
NASM
;; x, y, brightness
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putpixel:
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push ebp
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mov ebp, esp
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push eax
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push ebx
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push ecx
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push edi
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; check pixel is in screen
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mov ebx, [ebp+12] ;y
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cmp ebx, [mbootinfo.fb_height]
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jge .done
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mov ecx, [ebp+8] ;x
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cmp ecx, [mbootinfo.fb_width]
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jge .done
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; Destination
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mov edi, [mbootinfo.fb_addr]
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mov eax, [mbootinfo.fb_pitch]
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mul dword ebx ;y
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add edi, eax
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mov eax, ecx ;x
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movzx ecx, byte [mbootinfo.fb_bytespp]
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mul ecx
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add edi, eax
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; Brightness
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mov eax, [ebp + 16]
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; Poke videomemory
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cld
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rep stosb
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.done:
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pop edi
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pop ecx
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pop ebx
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pop eax
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pop ebp
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ret
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