1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
|
.set noreorder
.set noat
.include "hwregs_a.h"
.section .text
.global ResetGraph # Resets the GPU and installs a
.type ResetGraph, @function # VSync event handler
ResetGraph:
addiu $sp, -0x20 # C style stack allocation (required if
sw $ra, 28($sp) # you call BIOS functions from asm)
sw $a0, 24($sp)
la $v0, _hooks_installed # Skip installing hooks if this function
lbu $v0, 0($v0) # has already been called before once
nop
bnez $v0, .skip_hook_init
nop
# Temporary, may help improve compatibility?
jal SetDefaultExitFromException
nop
jal ChangeClearPAD # Remove pad handler left by the BIOS
move $a0, $0
li $a0, 1
jal ChangeClearRCnt # Remove RCnt handler
move $a1, $0
jal _96_remove # Remove CD handling left by the BIOS
nop
lui $a3, 0x1f80 # Base address for I/O
lui $v0, 0x3b33 # Enables DMA channel 6 (for ClearOTag)
ori $v0, 0x3b33 # Enables DMA channel 2
sw $v0, DPCR($a3)
sw $0 , DICR($a3) # Clear DICR (not needed)
li $v0, 0x9 # Enable IRQ0 (vblank)
sw $v0, IMASK($a3)
# Set an event handler
li $a0, 0xf2000003 # RCntCNT3 (vsync class)
li $a1, 0x2
li $a2, 0x1000
la $a3, _vsync_func # VSync event handler
jal OpenEvent # Open a VSync event handler
# (PSXSDK style vsync handler)
nop
la $v1, _vsync_event_desc # Save event descriptor
sw $v0, 0($v1)
jal EnableEvent # Enable the opened event
move $a0, $v0
la $v0, _hooks_installed # Set installed flag
li $v1, 0x1
sb $v1, 0($v0)
la $v0, _vsync_counter # Clear VSync counter
sw $0 , 0($v0)
la $v0, _vsync_callback_func # Clear callback function
sw $0 , 0($v0)
jal ExitCriticalSection # Re-enable interrupts
nop
.skip_hook_init:
lui $a3, 0x1f80
lw $v0, GP1($a3) # Get video standard
lui $v1, 0x0010
and $v0, $v1
la $v1, _gpu_standard
beqz $v0, .not_pal
sw $0 , 0($v1)
li $v0, 1
sw $v0, 0($v1)
.not_pal:
lw $a0, 24($sp) # Get argument value
lui $a3, 0x1f80 # Set base I/O again (likely destroyed
# by previous calls)
li $v0, 0x1d00 # Configure timer 1 as Hblank counter
sw $v0, T1_MODE($a3) # Set timer 1 value
li $at, 1
beq $a0, $at, .gpu_init_1
nop
li $at, 3
beq $a0, $at, .gpu_init_3
nop
sw $0 , GP1($a3) # Reset the GPU
b .init_done
nop
.gpu_init_1:
sw $0 , D2_CHCR($a3) # Stop any DMA
.gpu_init_3:
li $v0, 0x1 # Reset the command buffer
sw $v0, GP1($a3)
.init_done:
lw $ra, 28($sp)
lw $a0, 24($sp) # Return
jr $ra
addiu $sp, 0x20
.global _vsync_func # VSync event handler, executed on
.type _vsync_func, @function # every VBlank
_vsync_func:
la $gp, _gp
lui $at, 0x1f80 # Check if there's a VSync IRQ
lw $v0, IMASK($at)
nop
andi $v0, $v0, 0x1
beqz $v0, .exit
nop
lw $v1, ISTAT($at)
nop
andi $v0, $v1, 0x1
beqz $v0, .exit
nop
xori $v1, $v1, 0x1 # Acknowledge the IRQ
sw $v1, ISTAT($at)
la $v1, _vsync_counter # Increment VSync counter
lw $v0, 0($v1)
nop
addiu $v0, 1
sw $v0, 0($v1)
la $v0, _vsync_callback_func # Check if a callback function is set
lw $v0, 0($v0)
nop
beqz $v0, .exit
nop
addiu $sp, -0x20 # Save return address
sw $ra, 28($sp)
jalr $v0 # Execute user function
nop
lw $ra, 28($sp) # Restore previous return address
addiu $sp, 0x20
.exit:
jr $ra
nop
.global VSync # VSync function
.type VSync, @function
VSync:
addiu $sp, -4
sw $ra, 0($sp)
la $a1, _vsync_counter
lw $v0, 0($a1)
nop
.loop:
lw $v1, 0($a1)
nop
beq $v0, $v1, .loop
nop
la $v0, _gpu_current_field # Get last field value
lbu $v1, 0($v0)
.wait_field: # Wait for field bit to change
jal ReadGPUstat
nop
srl $v0, 31
beq $v0, $v1, .wait_field
nop
la $v1, _gpu_current_field # Store new field value
sb $v0, 0($v1)
lw $ra, 0($sp)
addiu $sp, 4
jr $ra
nop
.section .data
.global library_credits
.type library_credits, @object
library_credits:
.string "psxgpu programs by Lameguy64"
.type _vsync_counter, @object
_vsync_counter:
.word 0
.comm _vsync_callback_func, 4, 4
.comm _vsync_event_desc, 4, 4
.comm _gpu_standard, 4, 4
.comm _gpu_current_field, 4, 4
.comm _hooks_installed, 4, 4
|
