DrawPipe ASM

void CreatePipe() {
    time_t t;
    ushort _Image = (ushort)(CurPipe.Image + sizeof(TxtGFX));
    int _Size = CurPipe.Image->Size >> 1;
    int _Height = (rand() % 12) + 2;
    extern void DrawPipe_ASM(void);
    #pragma aux DrawPipe_ASM =  \
        "mov di, [_Image]"      \
        "mov ax, [_Height]"     \
        "mov cx, [_Size]"       \
        "mov bx, 0ADBh"         \
        "mov dx, 0B1B1h"        \
                                \
        "DrawRow:"              \
        "mov [di], dx"          \
        "mov [di+2], bx"        \
        "mov [di+4], bx"        \
        "mov [di+6], dx"        \
        "add di, 8"             \
        "sub cx, 4"             \
        "jz End"                \
        "dec ax"                \
        "jz HitHeight"          \
        "jmp DrawRow"           \
                                \
        "HitHeight:"            \
        "mov [di], bx"          \
        "mov [di+2], bx"        \
        "mov [di+4], bx"        \
        "mov [di+6], bx"        \
        "add di, 8"             \
        "mov si, 3"             \
        "DrawGap:"              \
        "mov [di], dx"          \
        "mov [di+2], dx"        \
        "mov [di+4], dx"        \
        "mov [di+6], dx"        \
        "add di, 8"             \
        "dec si"                \
        "jnz DrawGap"           \
        "mov [di], bx"          \
        "mov [di+2], bx"        \
        "mov [di+4], bx"        \
        "mov [di+6], bx"        \
        "add di, 8"             \
        "sub cx, 20"            \
        "mov ax, 0xFF"          \
        "jmp DrawRow"           \
                                \
        "End:"                  \
        modify [ax bx cx dx si di];
    //printf("%ld\n", time(&t));
    DrawPipe_ASM();
    //printf("%ld\n", time(&t));

    CurPipe.Height = _Height;
    PutGFX(30, 1, CurPipe.Image);
    UpdateScreen();
    return;