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blit_transparent_clip_tasm.cpp

Go to the documentation of this file.

#ifdef USE_TASM

extern "C" {

void blit_transparent_clip_asm_16bpp(unsigned char *src, unsigned short *dest, unsigned int width)
{
asm
{
ALIGN 8
blit_transparent_clip_asm_16bpp:
        push            esi                     ;; save used registers (5)
        push            edi
        push            eax
        push            ecx
        push            edx

        mov             esi, [esp+20+4] ;; load registers
        mov             edi, [esp+20+8]
        mov             edx, [esp+20+12]

        and             edx, edx
        jle             .rle_done               ;; just in case

        xor             ecx, ecx                ;; should produce smaller opcode than mov ecx, 0
ALIGN 4
.cmd_copy:
        mov             cx, [esi]
        sub             edx, ecx                ;; width -= rep
        jns             .do_copy                ;; if (rep >= width)
        add             ecx, edx                ;; rep = width

.do_copy:
        add             esi, 2

        shr             ecx, 1
        rep             movsd                   ;; copy all dwords

        jnc             .end_copy               ;; carry == ecx & 1 before the shift

        mov             ax, [esi]
        mov             [edi], ax
  add           esi,  2
        add             edi,  2

.end_copy:
        and             edx, edx                ;; if (width <= 0) jmp done
        jle             .rle_done   

.cmd_skip:
        mov             cx, [esi]               ;; read rep

        add             edi, ecx                ;; do the skip
        add             esi,  2
        add             edi, ecx                ;; (x2 because dest is word)

        sub             edx, ecx                ;; width -= rep
        jns             .cmd_copy    

.rle_done:
        pop             edx                     ;; restore used registers
        pop             ecx
        pop             eax
        pop             edi
        pop             esi

        ret
} //end asm
} //end blit_transparent_clip_asm_16bpp


void blit_transparent_clip_asm_32bpp(unsigned char *src, unsigned int *dest, unsigned int width)
{
asm
{
ALIGN 8
        push            esi                     ;; save used registers (4)
        push            edi
        push            ecx
        push            edx

        mov             esi, [esp+16+4] ;; load registers
        mov             edi, [esp+16+8]
        mov             edx, [esp+16+12]

        and             edx, edx
        jle             .rle_done32             ;; just in case

        xor             ecx, ecx                ;; should produce smaller opcode than mov ecx, 0
ALIGN 4
.cmd_copy32:
        mov             cx, [esi]
        sub             edx, ecx                ;; width -= rep
        jns             .do_copy32              ;; if (rep >= width)
        add             ecx, edx                ;; rep = width

.do_copy32:
  add           esi, 2
        rep             movsd                   ;; copy all dwords

        and             edx, edx                ;; if (width <= 0) jmp done
        jle             .rle_done32

.cmd_skip32:
        mov             cx, [esi]               ;; read rep
        lea             edi, [edi + 4*ecx]      ;; do the skip (x4 because dest is word)
        add             esi, 2

        sub             edx, ecx                ;; width -= rep
        jns             .cmd_copy32

.rle_done32:

        pop             edx                     ;; restore used registers
        pop             ecx
        pop             edi
        pop             esi

        ret
} //end asm
} // end blit_transparent_clip_asm_32bpp


} //end extern C


#endif

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