.global _bopti_gasm_mono
.global _bopti_gasm_mono_alpha
.global _bopti_gasm_gray
.global _bopti_gasm_gray_alpha

# REGISTER ALLOCATION
# r0: layer_1 (left)
# r1: layer_1 (right)
# r2: layer pointer and temp
# r3: mask pointer and temp
# --
# r4: vram light (left)
# r5: vram light (right)
# r6: vram dark (left)
# r7: vram dark (right)
# --
# @r15:      layer pointer
# @(4,r15):  mask pointer
# @(8,r15):  -(x&31)
# @(12,r15): destination

_bopti_gasm_mono:
	# Read the data longword and update the layer address
	mov.l	@r15, r2
	mov.l	@r2, r3
	mov.l	@r3+, r0
	mov.l	r3, @r2
	mov	r0, r1

	# Shift it
	mov.l	@(8, r15), r2
	shld	r2, r0
	add	#32, r2
	shld	r2, r1

	# Clear target VRAM and unwanted image data
	mov.l	@(4, r15), r3
	mov.l	@r3, r2
	and	r2, r0
	not	r2, r2
	and	r2, r4
	and	r2, r6
	mov.l	@(4, r3), r2
	and	r2, r1
	not	r2, r2
	and	r2, r5
	and	r2, r7

	# Join everything and return
	or	r0, r4
	or	r1, r5
	or	r0, r6
	or	r1, r7
	mov.l	@(12, r15), r2
	mov.l	r4, @r2
	mov.l	r5, @(4, r2)
	mov.l	r6, @(8, r2)
	rts
	mov.l	r7, @(12, r2)

# REGISTER ALLOCATION
# r0: layer_1 (left)
# r1: layer_1 (right)
# r2: layer_2 (left)
# r3: layer_2 (right)
# --
# r4: vram light (left)
# r5: vram light (right)
# r6: vram dark (left)
# r7: vram dark (right)
# --
# r8: layer pointer and temp
# r9: mask pointer and temp
# --
# @(8,r15):  layer pointer
# @(12,r15): mask pointer
# @(16,r15): -(x&31)
# @(20,r15): destination

_bopti_gasm_mono_alpha:
	mov.l	r8, @-r15
	mov.l	r9, @-r15

	# Read data longwords
	mov.l	@(8, r15), r8
	mov.l	@r8, r9
	mov.l	@r9+, r0
	mov.l	@r9+, r2
	mov.l	r9, @r8
	mov	r0, r1
	mov	r2, r3

	# Shift all layer data
	mov.l	@(16, r15), r8
	shld	r8, r0
	shld	r8, r2
	add	#32, r8
	shld	r8, r1
	shld	r8, r3

	# Apply masks on image data
	mov.l	@(12, r15), r9
	mov.l	@r9, r8
	and	r8, r0
	and	r8, r2
	mov.l	@(4, r9), r8
	and	r8, r1
	and	r8, r3

	# Render and leave
	not	r0, r0
	not	r1, r1
	and	r0, r4
	and	r1, r5
	and	r0, r6
	and	r1, r7
	or	r2, r4
	or	r3, r5
	or	r2, r6
	or	r3, r7
	mov.l	@(20, r15), r8
	mov.l	r4, @r8
	mov.l	r5, @(4, r8)
	mov.l	r6, @(8, r8)
	mov.l	r7, @(12, r8)

	mov.l	@r15+, r9
	rts
	mov.l	@r15+, r8

# REGISTER ALLOCATION
# r0: layer_1 (left)
# r1: layer_1 (right)
# r2: layer_2 (left)
# r3: layer_2 (right)
# --
# r4: vram light (left)
# r5: vram light (right)
# r6: vram dark (left)
# r7: vram dark (right)
# --
# r8: layer pointer (also +- x&31)
# r9: mask pointer (also layer)
# --
# @(8,r15):  layer pointer
# @(12,r15): mask pointer
# @(16,r15): -(x&31)
# @(20,r15): destination

_bopti_gasm_gray:
	mov.l	r8, @-r15
	mov.l	r9, @-r15

	# Read data longwords and update the layer address pointer
	mov.l	@(8, r15), r8
	mov.l	@r8, r9
	mov.l	@r9+, r0
	mov.l	@r9+, r2
	mov.l	r9, @r8
	mov	r0, r1
	mov	r2, r3

	# Shift all layer data
	mov.l	@(16, r15), r8
	shld	r8, r0
	shld	r8, r2
	add	#32, r8
	shld	r8, r1
	shld	r8, r3

	# On the left side, clear the VRAM which is about to be rewritten using
	# the left mask, and also clear unwanted image data
	mov.l	@(12, r15), r9
	mov.l	@r9, r8
	and	r8, r0
	and	r8, r2
	not	r8, r8
	and	r8, r4
	and	r8, r6

	# Same on the right side
	mov.l	@(4, r9), r8
	and	r8, r1
	and	r8, r3
	not	r8, r8
	and	r8, r5
	and	r8, r7

	# Render these together and store the result
	or	r0, r4
	or	r1, r5
	or	r2, r6
	or	r3, r7
	mov.l	@(20, r15), r8
	mov.l	r4, @r8
	mov.l	r5, @(4, r8)
	mov.l	r6, @(8, r8)
	mov.l	r7, @(12, r8)

	mov.l	@r15+, r9
	rts
	mov.l	@r15+, r8


# REGISTER ALLOCATION
# r0: layer_1 (left)
# r1: layer_1 (right)
# r2: layer_2 (left)
# r3: layer_2 (right)
# --
# r4: vram light (left)
# r5: vram light (right)
# r6: vram dark (left)
# r7: vram dark (right)
# --
# r8:  layer pointer (also +- x&31)
# r9:  mask pointer (also layer)
# r10: layer_3 (left)
# r11: layer_3 (right)
# --
# @(16,r15): layer pointer
# @(20,r15): mask pointer
# @(24,r15): -(x&31)
# @(28,r15): destination

.align 4
_bopti_gasm_gray_alpha:
	mov.l	r8, @-r15
	mov.l	r9, @-r15
	mov.l	r10, @-r15
	mov.l	r11, @-r15

	# Load layer data
	mov.l	@(16, r15), r8
	mov.l	@r8, r9
	mov.l	@r9+, r0
	mov.l	@r9+, r2
	mov	r0, r1
	mov.l	@r9+, r10
	mov	r2, r3
	mov.l	r9, @r8
	mov	r10, r11

	# Shift layer data
	mov.l	@(24, r15), r8
	shld	r8, r0
	shld	r8, r2
	shld	r8, r10
	add	#32, r8
	shld	r8, r1
	shld	r8, r3
	shld	r8, r11

	# Clear unwanted layer bits
	mov.l	@(20, r15), r9
	mov.l	@r9, r8
	and	r8, r0
	and	r8, r2
	and	r8, r10
	mov.l	@(4, r9), r8
	and	r8, r1
	and	r8, r3
	and	r8, r11

	# Blit everything
	not	r0, r0
	and	r0, r4
	and	r0, r6
	not 	r1, r1
	and	r1, r5
	and	r1, r7
	or	r2, r4
	or	r3, r5
	or	r10, r6
	or	r11, r7

	# Store results and leave
	mov.l	@(28, r15), r8
	mov.l	r4, @r8
	mov.l	r5, @(4, r8)
	mov.l	r6, @(8, r8)
	mov.l	r7, @(12, r8)
	mov.l	@r15+, r11
	mov.l	@r15+, r10
	mov.l	@r15+, r9
	rts
	mov.l	@r15+, r8