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comparison vdp.c @ 137:0e7e1ccc0a81

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Implemented HV counter
author Mike Pavone <pavone@retrodev.com>
date Sun, 30 Dec 2012 22:39:41 -0800
parents a81c548cf353
children aa3e1bb338c9
comparison
equal deleted inserted replaced
136:e64554246d11 137:0e7e1ccc0a81
1090 value |= 0x100; 1090 value |= 0x100;
1091 } 1091 }
1092 if (context->flags & FLAG_DMA_RUN) { 1092 if (context->flags & FLAG_DMA_RUN) {
1093 value |= 0x20; 1093 value |= 0x20;
1094 } 1094 }
1095 uint32_t line= context->cycles / MCLKS_LINE;
1096 if (line >= (context->latched_mode & BIT_PAL ? PAL_ACTIVE : NTSC_ACTIVE)) {
1097 value |= 0x8;
1098 }
1095 //TODO: Lots of other bits in status port 1099 //TODO: Lots of other bits in status port
1096 return value; 1100 return value;
1097 } 1101 }
1098 1102
1099 uint16_t vdp_data_port_read(vdp_context * context) 1103 uint16_t vdp_data_port_read(vdp_context * context)
1129 } 1133 }
1130 context->address += context->regs[REG_AUTOINC]; 1134 context->address += context->regs[REG_AUTOINC];
1131 return value; 1135 return value;
1132 } 1136 }
1133 1137
1138 uint16_t vdp_hv_counter_read(vdp_context * context)
1139 {
1140 uint32_t line= context->cycles / MCLKS_LINE;
1141 if (!line) {
1142 line = 0xFF;
1143 } else {
1144 line--;
1145 if (line > 0xEA) {
1146 line = (line + 0xFA) & 0xFF;
1147 }
1148 }
1149 uint32_t linecyc = context->cycles % MCLKS_LINE;
1150 if (context->latched_mode & BIT_H40) {
1151 linecyc /= 8;
1152 if (linecyc >= 86) {
1153 linecyc -= 86;
1154 } else {
1155 linecyc += 334;
1156 }
1157 if (linecyc > 0x16C) {
1158 linecyc += 92;
1159 }
1160 } else {
1161 linecyc /= 10;
1162 if (linecyc >= 74) {
1163 linecyc -= 74;
1164 } else {
1165 linecyc += 268;
1166 }
1167 if (linecyc > 0x127) {
1168 linecyc += 170;
1169 }
1170 }
1171 linecyc &= 0xFF;
1172 return (line << 8) | linecyc;
1173 }
1174
1134 void vdp_adjust_cycles(vdp_context * context, uint32_t deduction) 1175 void vdp_adjust_cycles(vdp_context * context, uint32_t deduction)
1135 { 1176 {
1136 context->cycles -= deduction; 1177 context->cycles -= deduction;
1137 for(fifo_entry * start = (context->fifo_end - FIFO_SIZE); start < context->fifo_cur; start++) { 1178 for(fifo_entry * start = (context->fifo_end - FIFO_SIZE); start < context->fifo_cur; start++) {
1138 if (start->cycle >= deduction) { 1179 if (start->cycle >= deduction) {