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comparison blastem.c @ 186:02e25abe2dcd

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Cleanup VINT code and fix bug in which VINT cycle would be set incorrectly after a VDP control port write
author Mike Pavone <pavone@retrodev.com>
date Sun, 13 Jan 2013 16:11:28 -0800
parents b204fbed4efe
children c615061f7914
comparison
equal deleted inserted replaced
185:b204fbed4efe 186:02e25abe2dcd
101 //TODO: Figure out what happens when you try to DMA from weird adresses like IO or banked Z80 area 101 //TODO: Figure out what happens when you try to DMA from weird adresses like IO or banked Z80 area
102 return 0; 102 return 0;
103 } 103 }
104 104
105 #define VINT_CYCLE ((MCLKS_LINE * 226)/MCLKS_PER_68K) 105 #define VINT_CYCLE ((MCLKS_LINE * 226)/MCLKS_PER_68K)
106
107 void adjust_int_cycle(m68k_context * context, vdp_context * v_context)
108 {
109 if (!(v_context->regs[REG_MODE_2] & 0x20 && ((context->status & 0x7) < 6)) || context->current_cycle >= VINT_CYCLE) {
110 context->int_cycle = CYCLE_NEVER;
111 context->target_cycle = context->sync_cycle;
112 } else if (context->int_cycle > VINT_CYCLE) {
113 context->int_cycle = VINT_CYCLE;
114 context->int_num = 6;
115 if (context->int_cycle < context->sync_cycle) {
116 context->target_cycle = context->int_cycle;
117 }
118 }
119 }
106 120
107 m68k_context * sync_components(m68k_context * context) 121 m68k_context * sync_components(m68k_context * context)
108 { 122 {
109 //TODO: Handle sync targets smaller than a single frame 123 //TODO: Handle sync targets smaller than a single frame
110 vdp_context * v_context = context->next_context; 124 vdp_context * v_context = context->next_context;
119 io_adjust_cycles(&gamepad_2, context->current_cycle, MCLKS_PER_FRAME/MCLKS_PER_68K); 133 io_adjust_cycles(&gamepad_2, context->current_cycle, MCLKS_PER_FRAME/MCLKS_PER_68K);
120 context->current_cycle -= MCLKS_PER_FRAME/MCLKS_PER_68K; 134 context->current_cycle -= MCLKS_PER_FRAME/MCLKS_PER_68K;
121 if (mclks) { 135 if (mclks) {
122 vdp_run_context(v_context, mclks); 136 vdp_run_context(v_context, mclks);
123 } 137 }
124 if (v_context->regs[REG_MODE_2] & 0x20 && ((context->status & 0x7) < 6)) {
125 if (context->int_cycle > VINT_CYCLE) {
126 context->int_cycle = VINT_CYCLE;
127 context->int_num = 6;
128 if (context->int_cycle < context->sync_cycle) {
129 context->target_cycle = context->int_cycle;
130 }
131 }
132 } else {
133 context->int_cycle = 0xFFFFFFFF;
134 context->target_cycle = context->sync_cycle;
135 }
136 } else { 138 } else {
137 //printf("running VDP for %d cycles\n", mclks - v_context->cycles); 139 //printf("running VDP for %d cycles\n", mclks - v_context->cycles);
138 vdp_run_context(v_context, mclks); 140 vdp_run_context(v_context, mclks);
139 if (v_context->regs[REG_MODE_2] & 0x20 && ((context->status & 0x7) < 6)) { 141 }
140 if (context->int_cycle > VINT_CYCLE) { 142 adjust_int_cycle(context, v_context);
141 context->int_cycle = VINT_CYCLE;
142 context->int_num = 6;
143 if (context->int_cycle < context->sync_cycle && context->int_cycle < context->current_cycle) {
144 context->target_cycle = context->int_cycle;
145 }
146 }
147 if (context->int_cycle <= context->current_cycle) {
148 context->int_cycle = CYCLE_NEVER;
149 context->target_cycle = context->sync_cycle;
150 }
151 } else {
152 context->int_cycle = CYCLE_NEVER;
153 context->target_cycle = context->sync_cycle;
154 }
155 }
156 return context; 143 return context;
157 } 144 }
158 145
159 m68k_context * vdp_port_write(uint32_t vdp_port, m68k_context * context, uint16_t value) 146 m68k_context * vdp_port_write(uint32_t vdp_port, m68k_context * context, uint16_t value)
160 { 147 {
195 blocked = 0; 182 blocked = 0;
196 } 183 }
197 } 184 }
198 context->current_cycle = v_context->cycles / MCLKS_PER_68K; 185 context->current_cycle = v_context->cycles / MCLKS_PER_68K;
199 } else { 186 } else {
200 if (v_context->regs[REG_MODE_2] & 0x20 && ((context->status & 0x7) < 6)) { 187 adjust_int_cycle(context, v_context);
201 if (context->int_cycle > VINT_CYCLE) {
202 context->int_cycle = VINT_CYCLE;
203 context->int_num = 6;
204 if (context->int_cycle < context->sync_cycle) {
205 context->target_cycle = context->int_cycle;
206 }
207 }
208 } else {
209 context->int_cycle = 0xFFFFFFFF;
210 context->target_cycle = context->sync_cycle;
211 }
212 } 188 }
213 } else { 189 } else {
214 printf("Illegal write to HV Counter port %X\n", vdp_port); 190 printf("Illegal write to HV Counter port %X\n", vdp_port);
215 exit(1); 191 exit(1);
216 } 192 }