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.align 2
.global expand_blend
.global expand_normal
@ Input:
@ r0 = screen_src_ptr
@ r1 = screen_dest_ptr
@ r2 = start
@ r3 = end
6:
.word io_registers
.word palette_ram_converted
.word 0x04000200 @ combine test mask
.word 0x07E0F81F @ clamp mask
.word 0x000003FE @ palette index mask
.word 0x08010020 @ saturation mask
expand_blend:
stmdb sp!, { r4, r5, r6, r9, r10, r11, r14 }
add r0, r0, r2, lsl #2 @ screen_src_ptr += start
add r1, r1, r2, lsl #1 @ screen_dest_ptr += start
sub r2, r3, r2 @ r2 = end - start
ldr r3, 6b @ r3 = io_registers
ldrh r3, [r3, #0x52] @ r3 = bldalpha
mov r4, r3, lsr #8 @ r4 = bldalpha >> 8
and r3, r3, #0x1F @ r3 = blend_a
and r4, r4, #0x1F @ r4 = blend_b
cmp r3, #16 @ if(blend_a > 16)
movgt r3, #16 @ blend_a = 16
cmp r4, #16 @ if(blend_b > 16)
movgt r4, #16 @ blend_b = 16
ldr r14, 6b + 4 @ r14 = palette_ram_converted
ldr r12, 6b + 8 @ r12 = 0x04000200
ldr r11, 6b + 12 @ r11 = 0x07E0F81F
ldr r10, 6b + 16 @ r10 = 0x000003FE
add r5, r3, r4 @ r5 = blend_a + blend_b
cmp r5, #16 @ if((blend_a + blend_b) > 16)
bgt 3f @ goto loop w/saturation
@ loop w/o saturation
1:
ldr r5, [r0], #4 @ r5 = pixel_pair, screen_src_ptr++
and r6, r5, r12 @ r6 = r5 & 0x04000200
cmp r6, r12 @ if(r6 != 0x4000200)
bne 2f @ goto no_blend
and r6, r10, r5, lsl #1 @ r6 = (pixel_pair & 0x1FF) << 1
ldrh r6, [r14, r6] @ r6 = pixel_top
orr r6, r6, r6, lsl #16 @ r6 = pixel_top | (pixel_top << 16)
and r6, r6, r11 @ r6 = pixel_top_dilated
and r5, r10, r5, lsr #15 @ r5 = ((pixel_pair >> 16) & 0x1FF) << 1
ldrh r5, [r14, r5] @ r5 = pixel_bottom
orr r5, r5, r5, lsl #16 @ r5 = pixel_bottom | (pixel_bottom << 16)
and r5, r5, r11 @ r5 = pixel_bottom_dilated
mul r5, r4, r5 @ r5 = pixel_bottom * blend_b = bottom_mul
mla r5, r3, r6, r5 @ r5 = (pixel_top * blend_a) + bottom_mul
and r5, r11, r5, lsr #4 @ r5 = (color_dilated >> 4) & 0x07E0F81F
orr r5, r5, r5, lsr #16 @ r5 = color_dilated | (color_dilated >> 16)
strh r5, [r1], #2 @ *screen_dest_ptr = r5, screen_dest_ptr++
subs r2, r2, #1 @ counter--
bne 1b @ go again
ldmia sp!, { r4, r5, r6, r9, r10, r11, pc }
2:
and r5, r10, r5, lsl #1 @ r5 = (pixel_pair & 0x1FF) << 1
ldrh r5, [r14, r5] @ r5 = pixel_top
strh r5, [r1], #2 @ *screen_dest_ptr = r5, screen_dest_ptr++
subs r2, r2, #1 @ counter--
bne 1b @ go again
ldmia sp!, { r4, r5, r6, r9, r10, r11, pc }
@ loop w/saturation
3:
ldr r9, 6b + 20 @ r9 = 0x08010020
4:
ldr r5, [r0], #4 @ r5 = pixel_pair, screen_src_ptr++
and r6, r5, r12 @ r6 = r5 & 0x04000200
cmp r6, r12 @ if(r6 != 0x4000200)
bne 5f @ goto no_blend
and r6, r10, r5, lsl #1 @ r6 = (pixel_pair & 0x1FF) << 1
ldrh r6, [r14, r6] @ r6 = pixel_top
orr r6, r6, r6, lsl #16 @ r6 = pixel_top | (pixel_top << 16)
and r6, r6, r11 @ r6 = pixel_top_dilated
and r5, r10, r5, lsr #15 @ r5 = ((pixel_pair >> 16) & 0x1FF) << 1
ldrh r5, [r14, r5] @ r5 = pixel_bottom
orr r5, r5, r5, lsl #16 @ r5 = pixel_bottom | (pixel_bottom << 16)
and r5, r5, r11 @ r5 = pixel_bottom_dilated
mul r5, r4, r5 @ r5 = pixel_bottom * blend_b = bottom_mul
mla r5, r3, r6, r5 @ r5 = (pixel_top * blend_a) + bottom_mul
and r6, r9, r5, lsr #4 @ r6 = saturation bits
orr r6, r6, r6, lsr #1 @ propogate saturation down msb
orr r6, r6, r6, lsr #2 @ propogate down next two bits
orr r6, r6, r6, lsr #3 @ propogate down next three bits
orr r5, r6, r5, lsr #4 @ mask over result w/saturation
and r5, r11, r5 @ r5 = (color_dilated >> 4) & 0x07E0F81F
orr r5, r5, r5, lsr #16 @ r5 = color_dilated | (color_dilated >> 16)
strh r5, [r1], #2 @ *screen_dest_ptr = r5, screen_dest_ptr++
subs r2, r2, #1 @ counter--
bne 4b @ go again
ldmia sp!, { r4, r5, r6, r9, r10, r11, pc }
5:
and r5, r10, r5, lsl #1 @ r5 = (pixel_pair & 0x1FF) << 1
ldrh r5, [r14, r5] @ r5 = pixel_top
strh r5, [r1], #2 @ *screen_dest_ptr = r5, screen_dest_ptr++
subs r2, r2, #1 @ counter--
bne 4b @ go again
ldmia sp!, { r4, r5, r6, r9, r10, r11, pc }
@ The following function isn't complete (only works on run multiples of 8),
@ but unfortunately I don't see much potential for actually being able to
@ use it..
#define expand_pixel_pair(reg, temp) ;\
and temp, r3, reg, lsr #15 ;\
ldrh temp, [r2, temp] ;\
;\
and reg, r3, reg, lsl #1 ;\
ldrh reg, [r2, reg] ;\
;\
orr reg, reg, temp, lsl #16 ;\
@ Input:
@ r0 = screen_ptr
@ r1 = start
@ r2 = end
1:
.word palette_ram_converted
.word 0x3FE
expand_normal:
stmdb sp!, { r4, r5, r6, r7, r14 }
add r0, r0, r1, lsl #1 @ screen_ptr += start
sub r1, r2, r1 @ r1 = end - start
ldr r2, 1b @ r2 = palette_ram_converted
ldr r3, 1b + 4 @ r3 = 0x3FE
2:
ldmia r0, { r4, r5, r6, r7 }
expand_pixel_pair(r4, r14)
expand_pixel_pair(r5, r14)
expand_pixel_pair(r6, r14)
expand_pixel_pair(r7, r14)
stmia r0!, { r4, r5, r6, r7 }
subs r1, r1, #8
bne 2b
ldmia sp!, { r4, r5, r6, r7, pc }
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