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comparison runtime.S @ 54:3b79cbcf6846

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Get Flavio's color bar demo kind of sort of working
author Mike Pavone <pavone@retrodev.com>
date Tue, 18 Dec 2012 02:16:42 -0800
parents 44e661913a51
children bc3bc7a60c4e
comparison
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53:44e661913a51 54:3b79cbcf6846
1 1
2 .global handle_cycle_limit 2 .global handle_cycle_limit
3 handle_cycle_limit: 3 handle_cycle_limit:
4 ret 4 call m68k_save_context
5 mov %rsi, %rdi
6 call sync_components
7 mov %rax, %rsi
8 call m68k_load_context
9 ret
10
11 do_vdp_port_write:
12 call m68k_save_context
13 mov %rcx, %rdx
14 call vdp_port_write
15 mov %rax, %rsi
16 call m68k_load_context
17 ret
18
19 do_vdp_port_read:
20 call m68k_save_context
21 call vdp_port_read
22 mov %rax, %rsi
23 call m68k_load_context
24 mov 120(%rsi), %cx
25 ret
26
27 bad_access_msg:
28 .asciz "Program tried to access illegal 68K address %X\n"
5 29
6 .global m68k_write_word 30 .global m68k_write_word
31 .global vdp_psg_w
7 m68k_write_word: 32 m68k_write_word:
8 and $0xFFFFFF, %rdi 33 and $0xFFFFFF, %rdi
9 cmp $0x400000, %edi 34 cmp $0x400000, %edi
10 jle cart_w 35 jle cart_w
11 cmp $0xE00000, %edi 36 cmp $0xE00000, %edi
12 jge workram_w 37 jge workram_w
38 cmp $0xC00000, %edi
39 jge vdp_psg_w
13 jmp inccycles 40 jmp inccycles
14 workram_w: 41 workram_w:
15 and $0xFFFF, %rdi 42 and $0xFFFF, %rdi
16 mov %cx, (%r9, %rdi) 43 mov %cx, (%r9, %rdi)
17 jmp inccycles 44 jmp inccycles
18 cart_w: 45 cart_w:
19 mov %cx, (%r8, %rdi) 46 mov %cx, (%r8, %rdi)
20 jmp inccycles 47 jmp inccycles
48 vdp_psg_w:
49 test $0x2700E0, %edi
50 jnz crash
51 and $0x1F, %edi
52 cmp $4, %edi
53 jl try_fifo_write
54 jmp do_vdp_port_write
55 try_fifo_write:
56 push %rdx
57 push %rbx
58 /* fetch VDP context pointer from 68K context */
59 mov 112(%rsi), %rdx
60 /* get fifo_cur and compare it to fifo_end */
61 mov (%rdx), %rbx
62 cmp %rbx, 8(%rdx)
63 /* bail out if fifo is full */
64 je fifo_fallback
65 /* populate FIFO entry */
66 mov %cx, 4(%rbx) /* value */
67 movb $0, 6(%rbx) /* partial */
68 mov %eax, %ecx
69 shl $3, %ecx /* multiply by 68K cycle by 7 to get MCLK cycle */
70 sub %eax, %ecx
71 mov %ecx, (%rbx) /* cycle */
72 /* update fifo_cur and store back in 68K context */
73 add $8, %rbx
74 mov %rbx, (%rdx)
75 /* clear pending flag */
76 andb $0xEF, 19(%rdx)
77 pop %rbx
78 pop %rdx
79 jmp inccycles
80 fifo_fallback:
81 pop %rbx
82 pop %rdx
83 jmp do_vdp_port_write
84 crash:
85 mov %edi, %esi
86 lea bad_access_msg(%rip), %rdi
87 call printf
88 mov $1, %rdi
89 call exit
21 90
22 .global m68k_write_byte 91 .global m68k_write_byte
23 m68k_write_byte: 92 m68k_write_byte:
24 and $0xFFFFFF, %rdi 93 and $0xFFFFFF, %rdi
25 /* deal with byte swapping */ 94 /* deal with byte swapping */
62 and $0xFFFFFF, %rcx 131 and $0xFFFFFF, %rcx
63 cmp $0x400000, %ecx 132 cmp $0x400000, %ecx
64 jle cart 133 jle cart
65 cmp $0xE00000, %ecx 134 cmp $0xE00000, %ecx
66 jge workram 135 jge workram
136 cmp $0xC00000, %edi
137 jge vdp_psg
67 xor %cx, %cx 138 xor %cx, %cx
139 dec %cx
68 jmp inccycles 140 jmp inccycles
69 workram: 141 workram:
70 and $0xFFFF, %rcx 142 and $0xFFFF, %rcx
71 mov (%r9, %rcx), %cx 143 mov (%r9, %rcx), %cx
72 jmp inccycles 144 jmp inccycles
145 vdp_psg:
146 test $0x2700E0, %edi
147 jnz crash
148 and $0x1F, %edi
149 jmp do_vdp_port_read
73 cart: 150 cart:
74 mov (%r8, %rcx), %cx 151 mov (%r8, %rcx), %cx
75 inccycles: 152 inccycles:
76 add $4, %rax 153 add $4, %rax
77 cmp %rbp, %rax 154 cmp %rbp, %rax
78 jge sync 155 jge handle_cycle_limit
79 ret
80 sync:
81 ret 156 ret
82 157
83 .global m68k_read_long_scratch1 158 .global m68k_read_long_scratch1
84 m68k_read_long_scratch1: 159 m68k_read_long_scratch1:
85 push %rcx 160 push %rcx
101 cmp $0x400000, %ecx 176 cmp $0x400000, %ecx
102 jle cart_b 177 jle cart_b
103 cmp $0xE00000, %ecx 178 cmp $0xE00000, %ecx
104 jge workram_b 179 jge workram_b
105 xor %cl, %cl 180 xor %cl, %cl
181 dec %cl
106 jmp inccycles 182 jmp inccycles
107 workram_b: 183 workram_b:
108 and $0xFFFF, %rcx 184 and $0xFFFF, %rcx
109 mov (%r9, %rcx), %cl 185 mov (%r9, %rcx), %cl
110 jmp inccycles 186 jmp inccycles
144 mov %r11d, 12(%rsi) /* d1 */ 220 mov %r11d, 12(%rsi) /* d1 */
145 mov %r12d, 16(%rsi) /* d2 */ 221 mov %r12d, 16(%rsi) /* d2 */
146 mov %r13d, 40(%rsi) /* a0 */ 222 mov %r13d, 40(%rsi) /* a0 */
147 mov %r14d, 44(%rsi) /* a1 */ 223 mov %r14d, 44(%rsi) /* a1 */
148 mov %r15d, 68(%rsi) /* a7 */ 224 mov %r15d, 68(%rsi) /* a7 */
225 mov %eax, 76(%rsi) /* current cycle count */
149 ret 226 ret
150 227
151 .global m68k_load_context 228 .global m68k_load_context
152 m68k_load_context: 229 m68k_load_context:
153 mov 1(%rsi), %bl /* N Flag */ 230 mov 1(%rsi), %bl /* N Flag */