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#368 minor asm optimizations

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This commit is contained in:
XProger
2022-01-31 04:12:51 +03:00
parent a0d7cf9821
commit 889d3af918
6 changed files with 95 additions and 145 deletions
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42
src/platform/gba/asm/rasterizeF.s
View File

@@ -16,9 +16,9 @@ DIVLUT .req r12
width .req lr
h .req N
Ry1 .req tmp
Rxy .req tmp
Ry2 .req Rh
Ly1 .req tmp
Lxy .req tmp
Ly2 .req Lh
LMAP .req Lx
pair .req DIVLUT
@@ -45,48 +45,40 @@ rasterizeF_asm:
cmp Lh, #0
bne .calc_left_end // if (Lh != 0) end with left
ldr N, [L, #VERTEX_PREV] // N = L->prev
ldrsh Ly1, [L, #VERTEX_Y] // Ly1 = L->v.y
ldr Lxy, [L, #VERTEX_X] // Lxy = (L->v.y << 16) | (L->v.x)
ldrsh Ly2, [N, #VERTEX_Y] // Ly2 = N->v.y
subs Lh, Ly2, Ly1 // Lh = Ly2 - Ly1
subs Lh, Ly2, Lxy, asr #16 // Lh = N->v.y - L->v.y
blt .exit // if (Lh < 0) return
ldrsh Lx, [L, #VERTEX_X] // Lx = L->v.x
lsl Lx, Lxy, #16 // Lx = L->v.x << 16
mov L, N // L = N
cmp Lh, #1 // if (Lh <= 1) skip Ldx calc
ble .skip_left_dx
ble .calc_left_start
lsl tmp, Lh, #1
ldrh tmp, [DIVLUT, tmp] // tmp = FixedInvU(Lh)
ldrsh Ldx, [N, #VERTEX_X]
sub Ldx, Lx
mul Ldx, tmp // Ldx = tmp * (N->v.x - Lx)
.skip_left_dx:
lsl Lx, #16 // Lx <<= 16
mov L, N // L = N
b .calc_left_start
ldrsh Ldx, [L, #VERTEX_X]
sub Ldx, Lx, asr #16
mul Ldx, tmp // Ldx = tmp * (N->v.x - L->v.x)
.calc_left_end:
.calc_right_start:
cmp Rh, #0
bne .calc_right_end // if (Rh != 0) end with right
ldr N, [R, #VERTEX_NEXT] // N = R->next
ldrsh Ry1, [R, #VERTEX_Y] // Ry1 = R->v.y
ldr Rxy, [R, #VERTEX_X] // Rxy = (R->v.y << 16) | (R->v.x)
ldrsh Ry2, [N, #VERTEX_Y] // Ry2 = N->v.y
subs Rh, Ry2, Ry1 // Rh = Ry2 - Ry1
subs Rh, Ry2, Rxy, asr #16 // Rh = N->v.y - R->v.y
blt .exit // if (Rh < 0) return
ldrsh Rx, [R, #VERTEX_X] // Rx = R->v.x
lsl Rx, Rxy, #16 // Rx = R->v.x << 16
mov R, N // R = N
cmp Rh, #1 // if (Rh <= 1) skip Rdx calc
ble .skip_right_dx
ble .calc_right_start
lsl tmp, Rh, #1
ldrh tmp, [DIVLUT, tmp] // tmp = FixedInvU(Rh)
ldrsh Rdx, [N, #VERTEX_X]
sub Rdx, Rx
ldrsh Rdx, [R, #VERTEX_X]
sub Rdx, Rx, asr #16
mul Rdx, tmp // Rdx = tmp * (N->v.x - Rx)
.skip_right_dx:
lsl Rx, #16 // Rx <<= 16
mov R, N // R = N
b .calc_right_start
.calc_right_end:
cmp Rh, Lh // if (Rh < Lh)

32
src/platform/gba/asm/rasterizeFT.s
View File

@@ -25,9 +25,9 @@ Rdt .req h
indexA .req Lh
indexB .req Rh
Ry1 .req tmp
Rxy .req tmp
Ry2 .req Rh
Ly1 .req tmp
Lxy .req tmp
Ly2 .req Lh
inv .req Lh
@@ -101,22 +101,22 @@ rasterizeFT_asm:
cmp Lh, #0
bne .calc_left_end // if (Lh != 0) end with left
ldr N, [L, #VERTEX_PREV] // N = L->prev
ldrsh Ly1, [L, #VERTEX_Y] // Ly1 = L->v.y
ldr Lxy, [L, #VERTEX_X] // Lxy = (L->v.y << 16) | (L->v.x)
ldrsh Ly2, [N, #VERTEX_Y] // Ly2 = N->v.y
subs Lh, Ly2, Ly1 // Lh = Ly2 - Ly1
subs Lh, Ly2, Lxy, asr #16 // Lh = N->v.y - L->v.y
blt .exit // if (Lh < 0) return
ldrsh Lx, [L, #VERTEX_X] // Lx = L->v.x
lsl Lx, Lxy, #16 // Lx = L->v.x << 16
ldr Lt, [L, #VERTEX_T] // Lt = L->t
mov L, N // L = N
cmp Lh, #1 // if (Lh <= 1) skip Ldx calc
ble .skip_left_dx
ble .calc_left_start
lsl tmp, Lh, #1
mov DIVLUT, #DIVLUT_ADDR
ldrh tmp, [DIVLUT, tmp] // tmp = FixedInvU(Lh)
ldrsh Ldx, [L, #VERTEX_X]
sub Ldx, Lx
sub Ldx, Lx, asr #16
mul Ldx, tmp // Ldx = tmp * (N->v.x - Lx)
str Ldx, [sp, #SP_LDX] // store Ldx to stack
@@ -131,32 +131,28 @@ rasterizeFT_asm:
lsl Ldu, #16
orr Ldt, Ldu, Ldv, lsr #16 // Ldt = (Rdu & 0xFFFF0000) | (Rdv >> 16)
str Ldt, [sp, #SP_LDT] // store Ldt to stack
.skip_left_dx:
lsl Lx, #16 // Lx <<= 16
b .calc_left_start
.calc_left_end:
.calc_right_start:
cmp Rh, #0
bne .calc_right_end // if (Rh != 0) end with right
ldr N, [R, #VERTEX_NEXT] // N = R->next
ldrsh Ry1, [R, #VERTEX_Y] // Ry1 = R->v.y
ldr Rxy, [R, #VERTEX_X] // Rxy = (R->v.y << 16) | (R->v.x)
ldrsh Ry2, [N, #VERTEX_Y] // Ry2 = N->v.y
subs Rh, Ry2, Ry1 // Rh = Ry2 - Ry1
subs Rh, Ry2, Rxy, asr #16 // Rh = Ry2 - Rxy
blt .exit // if (Rh < 0) return
ldrsh Rx, [R, #VERTEX_X] // Rx = R->v.x
lsl Rx, Rxy, #16 // Rx = R->v.x << 16
ldr Rt, [R, #VERTEX_T] // Rt = R->t
mov R, N // R = N
cmp Rh, #1 // if (Rh <= 1) skip Rdx calc
ble .skip_right_dx
ble .calc_right_start
lsl tmp, Rh, #1
mov DIVLUT, #DIVLUT_ADDR
ldrh tmp, [DIVLUT, tmp] // tmp = FixedInvU(Rh)
ldrsh Rdx, [R, #VERTEX_X]
sub Rdx, Rx
sub Rdx, Rx, asr #16
mul Rdx, tmp // Rdx = tmp * (N->v.x - Rx)
str Rdx, [sp, #SP_RDX] // store Rdx to stack
@@ -171,10 +167,6 @@ rasterizeFT_asm:
lsl Rdu, #16
orr Rdt, Rdu, Rdv, lsr #16 // Rdt = (Rdu & 0xFFFF0000) | (Rdv >> 16)
str Rdt, [sp, #SP_RDT] // store Rdt to stack
.skip_right_dx:
lsl Rx, #16 // Rx <<= 16
b .calc_right_start
.calc_right_end:
cmp Rh, Lh // if (Rh < Lh)

32
src/platform/gba/asm/rasterizeFTA.s
View File

@@ -25,9 +25,9 @@ Rdt .req h
indexA .req Lh
indexB .req Rh
Ry1 .req tmp
Rxy .req tmp
Ry2 .req Rh
Ly1 .req tmp
Lxy .req tmp
Ly2 .req Lh
inv .req Lh
@@ -107,22 +107,22 @@ rasterizeFTA_asm:
cmp Lh, #0
bne .calc_left_end // if (Lh != 0) end with left
ldr N, [L, #VERTEX_PREV] // N = L->prev
ldrsh Ly1, [L, #VERTEX_Y] // Ly1 = L->v.y
ldr Lxy, [L, #VERTEX_X] // Lxy = (L->v.y << 16) | (L->v.x)
ldrsh Ly2, [N, #VERTEX_Y] // Ly2 = N->v.y
subs Lh, Ly2, Ly1 // Lh = Ly2 - Ly1
subs Lh, Ly2, Lxy, asr #16 // Lh = N->v.y - L->v.y
blt .exit // if (Lh < 0) return
ldrsh Lx, [L, #VERTEX_X] // Lx = L->v.x
lsl Lx, Lxy, #16 // Lx = L->v.x << 16
ldr Lt, [L, #VERTEX_T] // Lt = L->t
mov L, N // L = N
cmp Lh, #1 // if (Lh <= 1) skip Ldx calc
ble .skip_left_dx
ble .calc_left_start
lsl tmp, Lh, #1
mov DIVLUT, #DIVLUT_ADDR
ldrh tmp, [DIVLUT, tmp] // tmp = FixedInvU(Lh)
ldrsh Ldx, [L, #VERTEX_X]
sub Ldx, Lx
sub Ldx, Lx, asr #16
mul Ldx, tmp // Ldx = tmp * (N->v.x - Lx)
str Ldx, [sp, #SP_LDX] // store Ldx to stack
@@ -137,32 +137,28 @@ rasterizeFTA_asm:
lsl Ldu, #16
orr Ldt, Ldu, Ldv, lsr #16 // Ldt = (Rdu & 0xFFFF0000) | (Rdv >> 16)
str Ldt, [sp, #SP_LDT] // store Ldt to stack
.skip_left_dx:
lsl Lx, #16 // Lx <<= 16
b .calc_left_start
.calc_left_end:
.calc_right_start:
cmp Rh, #0
bne .calc_right_end // if (Rh != 0) end with right
ldr N, [R, #VERTEX_NEXT] // N = R->next
ldrsh Ry1, [R, #VERTEX_Y] // Ry1 = R->v.y
ldr Rxy, [R, #VERTEX_X] // Rxy = (R->v.y << 16) | (R->v.x)
ldrsh Ry2, [N, #VERTEX_Y] // Ry2 = N->v.y
subs Rh, Ry2, Ry1 // Rh = Ry2 - Ry1
subs Rh, Ry2, Rxy, asr #16 // Rh = N->v.y - R->v.y
blt .exit // if (Rh < 0) return
ldrsh Rx, [R, #VERTEX_X] // Rx = R->v.x
lsl Rx, Rxy, #16 // Rx = R->v.x << 16
ldr Rt, [R, #VERTEX_T] // Rt = R->t
mov R, N // R = N
cmp Rh, #1 // if (Rh <= 1) skip Rdx calc
ble .skip_right_dx
ble .calc_right_start
lsl tmp, Rh, #1
mov DIVLUT, #DIVLUT_ADDR
ldrh tmp, [DIVLUT, tmp] // tmp = FixedInvU(Rh)
ldrsh Rdx, [R, #VERTEX_X]
sub Rdx, Rx
sub Rdx, Rx, asr #16
mul Rdx, tmp // Rdx = tmp * (N->v.x - Rx)
str Rdx, [sp, #SP_RDX] // store Rdx to stack
@@ -177,10 +173,6 @@ rasterizeFTA_asm:
lsl Rdu, #16
orr Rdt, Rdu, Rdv, lsr #16 // Rdt = (Rdu & 0xFFFF0000) | (Rdv >> 16)
str Rdt, [sp, #SP_RDT] // store Rdt to stack
.skip_right_dx:
lsl Rx, #16 // Rx <<= 16
b .calc_right_start
.calc_right_end:
cmp Rh, Lh // if (Rh < Lh)

47
src/platform/gba/asm/rasterizeGT.s
View File

@@ -37,9 +37,9 @@ Rdt .req h
indexA .req Lh
indexB .req Rh
Ry1 .req tmp
Rxy .req tmp
Ry2 .req Rh
Ly1 .req tmp
Lxy .req tmp
Ly2 .req Lh
inv .req Lh
@@ -123,28 +123,29 @@ rasterizeGT_asm:
cmp Lh, #0
bne .calc_left_end // if (Lh != 0) end with left
ldr N, [L, #VERTEX_PREV] // N = L->prev
ldrsh Ly1, [L, #VERTEX_Y] // Ly1 = L->v.y
ldr Lxy, [L, #VERTEX_X] // Lxy = (L->v.y << 16) | (L->v.x)
ldrsh Ly2, [N, #VERTEX_Y] // Ly2 = N->v.y
subs Lh, Ly2, Ly1 // Lh = Ly2 - Ly1
subs Lh, Ly2, Lxy, asr #16 // Lh = N->v.y - L->v.y
blt .exit // if (Lh < 0) return
ldrsh Lx, [L, #VERTEX_X] // Lx = L->v.x
lsl Lx, Lxy, #16 // Lx = L->v.x << 16
ldrb Lg, [L, #VERTEX_G] // Lg = L->v.g
ldr Lt, [L, #VERTEX_T] // Lt = L->t
mov L, N // L = N
lsl Lg, #8 // Lg <<= 8
cmp Lh, #1 // if (Lh <= 1) skip Ldx calc
ble .skip_left_dx
ble .calc_left_start
lsl tmp, Lh, #1
mov DIVLUT, #DIVLUT_ADDR
ldrh tmp, [DIVLUT, tmp] // tmp = FixedInvU(Lh)
ldrsh Ldx, [L, #VERTEX_X]
sub Ldx, Lx
sub Ldx, Lx, asr #16
mul Ldx, tmp // Ldx = tmp * (N->v.x - Lx)
str Ldx, [sp, #SP_LDX] // store Ldx to stack
ldrb Ldg, [L, #VERTEX_G]
sub Ldg, Lg
sub Ldg, Lg, lsr #8
mul Ldg, tmp // Ldg = tmp * (N->v.g - Lg)
asr Ldg, #8 // 8-bit for fractional part
str Ldg, [sp, #SP_LDG] // store Ldg to stack
@@ -160,41 +161,35 @@ rasterizeGT_asm:
lsl Ldu, #16
orr Ldt, Ldu, Ldv, lsr #16 // Ldt = (Rdu & 0xFFFF0000) | (Rdv >> 16)
str Ldt, [sp, #SP_LDT] // store Ldt to stack
.skip_left_dx:
lsl Lx, #16 // Lx <<= 16
lsl Lg, #8 // Lg <<= 8
add Lg, #LMAP_ADDR // Lg += lightmap
b .calc_left_start
.calc_left_end:
.calc_right_start:
cmp Rh, #0
bne .calc_right_end // if (Rh != 0) end with right
ldr N, [R, #VERTEX_NEXT] // N = R->next
ldrsh Ry1, [R, #VERTEX_Y] // Ry1 = R->v.y
ldr Rxy, [R, #VERTEX_X] // Rxy = (R->v.y << 16) | (R->v.x)
ldrsh Ry2, [N, #VERTEX_Y] // Ry2 = N->v.y
subs Rh, Ry2, Ry1 // Rh = Ry2 - Ry1
subs Rh, Ry2, Rxy, asr #16 // Rh = N->v.y - R->v.y
blt .exit // if (Rh < 0) return
ldrsh Rx, [R, #VERTEX_X] // Rx = R->v.x
lsl Rx, Rxy, #16 // Rx = R->v.x << 16
ldrb Rg, [R, #VERTEX_G] // Rg = R->v.g
ldr Rt, [R, #VERTEX_T] // Rt = R->t
mov R, N // R = N
lsl Rg, #8 // Rg <<= 8
cmp Rh, #1 // if (Rh <= 1) skip Rdx calc
ble .skip_right_dx
ble .calc_right_start
lsl tmp, Rh, #1
mov DIVLUT, #DIVLUT_ADDR
ldrh tmp, [DIVLUT, tmp] // tmp = FixedInvU(Rh)
ldrsh Rdx, [R, #VERTEX_X]
sub Rdx, Rx
sub Rdx, Rx, asr #16
mul Rdx, tmp // Rdx = tmp * (N->v.x - Rx)
str Rdx, [sp, #SP_RDX] // store Rdx to stack
ldrb Rdg, [R, #VERTEX_G]
sub Rdg, Rg
sub Rdg, Rg, lsr #8
mul Rdg, tmp // Rdg = tmp * (N->v.g - Rg)
asr Rdg, #8 // 8-bit for fractional part
str Rdg, [sp, #SP_RDG] // store Ldg to stack
@@ -210,15 +205,11 @@ rasterizeGT_asm:
lsl Rdu, #16
orr Rdt, Rdu, Rdv, lsr #16 // Rdt = (Rdu & 0xFFFF0000) | (Rdv >> 16)
str Rdt, [sp, #SP_RDT] // store Rdt to stack
.skip_right_dx:
lsl Rx, #16 // Rx <<= 16
lsl Rg, #8 // Rg <<= 8
add Rg, #LMAP_ADDR // Rg += lightmap
b .calc_right_start
.calc_right_end:
orr Lg, #LMAP_ADDR
orr Rg, #LMAP_ADDR
cmp Rh, Lh // if (Rh < Lh)
movlt h, Rh // h = Rh
movge h, Lh // else h = Lh

47
src/platform/gba/asm/rasterizeGTA.s
View File

@@ -37,9 +37,9 @@ Rdt .req h
indexA .req Lh
indexB .req Rh
Ry1 .req tmp
Rxy .req tmp
Ry2 .req Rh
Ly1 .req tmp
Lxy .req tmp
Ly2 .req Lh
inv .req Lh
@@ -128,28 +128,29 @@ rasterizeGTA_asm:
cmp Lh, #0
bne .calc_left_end // if (Lh != 0) end with left
ldr N, [L, #VERTEX_PREV] // N = L->prev
ldrsh Ly1, [L, #VERTEX_Y] // Ly1 = L->v.y
ldr Lxy, [L, #VERTEX_X] // Lxy = (L->v.y << 16) | (L->v.x)
ldrsh Ly2, [N, #VERTEX_Y] // Ly2 = N->v.y
subs Lh, Ly2, Ly1 // Lh = Ly2 - Ly1
subs Lh, Ly2, Lxy, asr #16 // Lh = N->v.y - L->v.y
blt .exit // if (Lh < 0) return
ldrsh Lx, [L, #VERTEX_X] // Lx = L->v.x
lsl Lx, Lxy, #16 // Lx = L->v.x << 16
ldrb Lg, [L, #VERTEX_G] // Lg = L->v.g
ldr Lt, [L, #VERTEX_T] // Lt = L->t
mov L, N // L = N
lsl Lg, #8 // Lg <<= 8
cmp Lh, #1 // if (Lh <= 1) skip Ldx calc
ble .skip_left_dx
ble .calc_left_start
lsl tmp, Lh, #1
mov DIVLUT, #DIVLUT_ADDR
ldrh tmp, [DIVLUT, tmp] // tmp = FixedInvU(Lh)
ldrsh Ldx, [L, #VERTEX_X]
sub Ldx, Lx
sub Ldx, Lx, asr #16
mul Ldx, tmp // Ldx = tmp * (N->v.x - Lx)
str Ldx, [sp, #SP_LDX] // store Ldx to stack
ldrb Ldg, [L, #VERTEX_G]
sub Ldg, Lg
sub Ldg, Lg, lsr #8
mul Ldg, tmp // Ldg = tmp * (N->v.g - Lg)
asr Ldg, #8 // 8-bit for fractional part
str Ldg, [sp, #SP_LDG] // store Ldg to stack
@@ -165,41 +166,35 @@ rasterizeGTA_asm:
lsl Ldu, #16
orr Ldt, Ldu, Ldv, lsr #16 // Ldt = (Rdu & 0xFFFF0000) | (Rdv >> 16)
str Ldt, [sp, #SP_LDT] // store Ldt to stack
.skip_left_dx:
lsl Lx, #16 // Lx <<= 16
lsl Lg, #8 // Lg <<= 8
add Lg, #LMAP_ADDR // Lg += lightmap
b .calc_left_start
.calc_left_end:
.calc_right_start:
cmp Rh, #0
bne .calc_right_end // if (Rh != 0) end with right
ldr N, [R, #VERTEX_NEXT] // N = R->next
ldrsh Ry1, [R, #VERTEX_Y] // Ry1 = R->v.y
ldr Rxy, [R, #VERTEX_X] // Rxy = (R->v.y << 16) | (R->v.x)
ldrsh Ry2, [N, #VERTEX_Y] // Ry2 = N->v.y
subs Rh, Ry2, Ry1 // Rh = Ry2 - Ry1
subs Rh, Ry2, Rxy, asr #16 // Rh = N->v.y - R->v.y
blt .exit // if (Rh < 0) return
ldrsh Rx, [R, #VERTEX_X] // Rx = R->v.x
lsl Rx, Rxy, #16 // Rx = R->v.x << 16
ldrb Rg, [R, #VERTEX_G] // Rg = R->v.g
ldr Rt, [R, #VERTEX_T] // Rt = R->t
mov R, N // R = N
lsl Rg, #8 // Rg <<= 8
cmp Rh, #1 // if (Rh <= 1) skip Rdx calc
ble .skip_right_dx
ble .calc_right_start
lsl tmp, Rh, #1
mov DIVLUT, #DIVLUT_ADDR
ldrh tmp, [DIVLUT, tmp] // tmp = FixedInvU(Rh)
ldrsh Rdx, [R, #VERTEX_X]
sub Rdx, Rx
sub Rdx, Rx, asr #16
mul Rdx, tmp // Rdx = tmp * (N->v.x - Rx)
str Rdx, [sp, #SP_RDX] // store Rdx to stack
ldrb Rdg, [R, #VERTEX_G]
sub Rdg, Rg
sub Rdg, Rg, lsr #8
mul Rdg, tmp // Rdg = tmp * (N->v.g - Rg)
asr Rdg, #8 // 8-bit for fractional part
str Rdg, [sp, #SP_RDG] // store Ldg to stack
@@ -215,15 +210,11 @@ rasterizeGTA_asm:
lsl Rdu, #16
orr Rdt, Rdu, Rdv, lsr #16 // Rdt = (Rdu & 0xFFFF0000) | (Rdv >> 16)
str Rdt, [sp, #SP_RDT] // store Rdt to stack
.skip_right_dx:
lsl Rx, #16 // Rx <<= 16
lsl Rg, #8 // Rg <<= 8
add Rg, #LMAP_ADDR // Rg += lightmap
b .calc_right_start
.calc_right_end:
orr Lg, #LMAP_ADDR
orr Rg, #LMAP_ADDR
cmp Rh, Lh // if (Rh < Lh)
movlt h, Rh // h = Rh
movge h, Lh // else h = Lh

40
src/platform/gba/asm/rasterizeS.s
View File

@@ -15,9 +15,9 @@ tmp .req r11
DIVLUT .req r12
width .req lr
h .req N
Ry1 .req tmp
Rxy .req tmp
Ry2 .req Rh
Ly1 .req tmp
Lxy .req tmp
Ly2 .req Lh
pair .req DIVLUT
indexA .req Lh
@@ -42,48 +42,40 @@ rasterizeS_asm:
cmp Lh, #0
bne .calc_left_end // if (Lh != 0) end with left
ldr N, [L, #VERTEX_PREV] // N = L->prev
ldrsh Ly1, [L, #VERTEX_Y] // Ly1 = L->v.y
ldr Lxy, [L, #VERTEX_X] // Lxy = (L->v.y << 16) | (L->v.x)
ldrsh Ly2, [N, #VERTEX_Y] // Ly2 = N->v.y
subs Lh, Ly2, Ly1 // Lh = Ly2 - Ly1
subs Lh, Ly2, Lxy, asr #16 // Lh = N->v.y - L->v.y
blt .exit // if (Lh < 0) return
ldrsh Lx, [L, #VERTEX_X] // Lx = L->v.x
lsl Lx, Lxy, #16 // Lx = L->v.x << 16
mov L, N // L = N
cmp Lh, #1 // if (Lh <= 1) skip Ldx calc
ble .skip_left_dx
ble .calc_left_start
lsl tmp, Lh, #1
ldrh tmp, [DIVLUT, tmp] // tmp = FixedInvU(Lh)
ldrsh Ldx, [N, #VERTEX_X]
sub Ldx, Lx
ldrsh Ldx, [L, #VERTEX_X]
sub Ldx, Lx, asr #16
mul Ldx, tmp // Ldx = tmp * (N->v.x - Lx)
.skip_left_dx:
lsl Lx, #16 // Lx <<= 16
mov L, N // L = N
b .calc_left_start
.calc_left_end:
.calc_right_start:
cmp Rh, #0
bne .calc_right_end // if (Rh != 0) end with right
ldr N, [R, #VERTEX_NEXT] // N = R->next
ldrsh Ry1, [R, #VERTEX_Y] // Ry1 = R->v.y
ldr Rxy, [R, #VERTEX_X] // Rxy = (R->v.y << 16) | (R->v.x)
ldrsh Ry2, [N, #VERTEX_Y] // Ry2 = N->v.y
subs Rh, Ry2, Ry1 // Rh = Ry2 - Ry1
subs Rh, Ry2, Rxy, asr #16 // Rh = N->v.y - R->v.y
blt .exit // if (Rh < 0) return
ldrsh Rx, [R, #VERTEX_X] // Rx = R->v.x
lsl Rx, Rxy, #16 // Rx = R->v.x << 16
mov R, N // R = N
cmp Rh, #1 // if (Rh <= 1) skip Rdx calc
ble .skip_right_dx
ble .calc_right_start
lsl tmp, Rh, #1
ldrh tmp, [DIVLUT, tmp] // tmp = FixedInvU(Rh)
ldrsh Rdx, [N, #VERTEX_X]
sub Rdx, Rx
ldrsh Rdx, [R, #VERTEX_X]
sub Rdx, Rx, asr #16
mul Rdx, tmp // Rdx = tmp * (N->v.x - Rx)
.skip_right_dx:
lsl Rx, #16 // Rx <<= 16
mov R, N // R = N
b .calc_right_start
.calc_right_end:
cmp Rh, Lh // if (Rh < Lh)