Mercurial > repos > blastem

comparison vdp.c @ 1344:6372de4da179

Find changesets by keywords (author, files, the commit message), revision number or hash, or revset expression.
Fix vscroll latching when full screen vscroll is used in combination with the window plane on the left side of the screen
author Michael Pavone <pavone@retrodev.com>
date Fri, 05 May 2017 22:08:30 -0700
parents 033dda2d4598
children f7ca42e020fd
comparison
equal deleted inserted replaced
1343:033dda2d4598 1344:6372de4da179
1050 } else { 1050 } else {
1051 window_line_shift = 3; 1051 window_line_shift = 3;
1052 v_offset_mask = 0x7; 1052 v_offset_mask = 0x7;
1053 vscroll_shift = 3; 1053 vscroll_shift = 3;
1054 } 1054 }
1055 if (!vsram_off) {
1056 uint16_t left_col, right_col;
1057 if (context->regs[REG_WINDOW_H] & WINDOW_RIGHT) {
1058 left_col = (context->regs[REG_WINDOW_H] & 0x1F) * 2 + 2;
1059 right_col = 42;
1060 } else {
1061 left_col = 0;
1062 right_col = (context->regs[REG_WINDOW_H] & 0x1F) * 2;
1063 if (right_col) {
1064 right_col += 2;
1065 }
1066 }
1067 uint16_t top_line, bottom_line;
1068 if (context->regs[REG_WINDOW_V] & WINDOW_DOWN) {
1069 top_line = (context->regs[REG_WINDOW_V] & 0x1F) << window_line_shift;
1070 bottom_line = context->double_res ? 481 : 241;
1071 } else {
1072 top_line = 0;
1073 bottom_line = (context->regs[REG_WINDOW_V] & 0x1F) << window_line_shift;
1074 }
1075 if ((column >= left_col && column < right_col) || (line >= top_line && line < bottom_line)) {
1076 uint16_t address = context->regs[REG_WINDOW] << 10;
1077 uint16_t line_offset, offset, mask;
1078 if (context->regs[REG_MODE_4] & BIT_H40) {
1079 address &= 0xF000;
1080 line_offset = (((line) >> vscroll_shift) * 64 * 2) & 0xFFF;
1081 mask = 0x7F;
1082
1083 } else {
1084 address &= 0xF800;
1085 line_offset = (((line) >> vscroll_shift) * 32 * 2) & 0xFFF;
1086 mask = 0x3F;
1087 }
1088 if (context->double_res) {
1089 mask <<= 1;
1090 mask |= 1;
1091 }
1092 offset = address + line_offset + (((column - 2) * 2) & mask);
1093 context->col_1 = (context->vdpmem[offset] << 8) | context->vdpmem[offset+1];
1094 //printf("Window | top: %d, bot: %d, left: %d, right: %d, base: %X, line: %X offset: %X, tile: %X, reg: %X\n", top_line, bottom_line, left_col, right_col, address, line_offset, offset, ((context->col_1 & 0x3FF) << 5), context->regs[REG_WINDOW]);
1095 offset = address + line_offset + (((column - 1) * 2) & mask);
1096 context->col_2 = (context->vdpmem[offset] << 8) | context->vdpmem[offset+1];
1097 context->v_offset = (line) & v_offset_mask;
1098 context->flags |= FLAG_WINDOW;
1099 return;
1100 }
1101 context->flags &= ~FLAG_WINDOW;
1102 }
1103 //TODO: Verify behavior for 0x20 case
1104 uint16_t vscroll = 0xFF | (context->regs[REG_SCROLL] & 0x30) << 4;
1105 if (context->double_res) {
1106 vscroll <<= 1;
1107 vscroll |= 1;
1108 }
1109 //TODO: Further research on vscroll latch behavior and the "first column bug" 1055 //TODO: Further research on vscroll latch behavior and the "first column bug"
1110 if (!column) { 1056 if (!column) {
1111 if (context->regs[REG_MODE_3] & BIT_VSCROLL) { 1057 if (context->regs[REG_MODE_3] & BIT_VSCROLL) {
1112 if (context->regs[REG_MODE_4] & BIT_H40) { 1058 if (context->regs[REG_MODE_4] & BIT_H40) {
1113 //Based on observed behavior documented by Eke-Eke, I'm guessing the VDP 1059 //Based on observed behavior documented by Eke-Eke, I'm guessing the VDP
1123 } else { 1069 } else {
1124 context->vscroll_latch[vsram_off] = context->vsram[vsram_off]; 1070 context->vscroll_latch[vsram_off] = context->vsram[vsram_off];
1125 } 1071 }
1126 } else if (context->regs[REG_MODE_3] & BIT_VSCROLL) { 1072 } else if (context->regs[REG_MODE_3] & BIT_VSCROLL) {
1127 context->vscroll_latch[vsram_off] = context->vsram[column - 2 + vsram_off]; 1073 context->vscroll_latch[vsram_off] = context->vsram[column - 2 + vsram_off];
1074 }
1075 if (!vsram_off) {
1076 uint16_t left_col, right_col;
1077 if (context->regs[REG_WINDOW_H] & WINDOW_RIGHT) {
1078 left_col = (context->regs[REG_WINDOW_H] & 0x1F) * 2 + 2;
1079 right_col = 42;
1080 } else {
1081 left_col = 0;
1082 right_col = (context->regs[REG_WINDOW_H] & 0x1F) * 2;
1083 if (right_col) {
1084 right_col += 2;
1085 }
1086 }
1087 uint16_t top_line, bottom_line;
1088 if (context->regs[REG_WINDOW_V] & WINDOW_DOWN) {
1089 top_line = (context->regs[REG_WINDOW_V] & 0x1F) << window_line_shift;
1090 bottom_line = context->double_res ? 481 : 241;
1091 } else {
1092 top_line = 0;
1093 bottom_line = (context->regs[REG_WINDOW_V] & 0x1F) << window_line_shift;
1094 }
1095 if ((column >= left_col && column < right_col) || (line >= top_line && line < bottom_line)) {
1096 uint16_t address = context->regs[REG_WINDOW] << 10;
1097 uint16_t line_offset, offset, mask;
1098 if (context->regs[REG_MODE_4] & BIT_H40) {
1099 address &= 0xF000;
1100 line_offset = (((line) >> vscroll_shift) * 64 * 2) & 0xFFF;
1101 mask = 0x7F;
1102
1103 } else {
1104 address &= 0xF800;
1105 line_offset = (((line) >> vscroll_shift) * 32 * 2) & 0xFFF;
1106 mask = 0x3F;
1107 }
1108 if (context->double_res) {
1109 mask <<= 1;
1110 mask |= 1;
1111 }
1112 offset = address + line_offset + (((column - 2) * 2) & mask);
1113 context->col_1 = (context->vdpmem[offset] << 8) | context->vdpmem[offset+1];
1114 //printf("Window | top: %d, bot: %d, left: %d, right: %d, base: %X, line: %X offset: %X, tile: %X, reg: %X\n", top_line, bottom_line, left_col, right_col, address, line_offset, offset, ((context->col_1 & 0x3FF) << 5), context->regs[REG_WINDOW]);
1115 offset = address + line_offset + (((column - 1) * 2) & mask);
1116 context->col_2 = (context->vdpmem[offset] << 8) | context->vdpmem[offset+1];
1117 context->v_offset = (line) & v_offset_mask;
1118 context->flags |= FLAG_WINDOW;
1119 return;
1120 }
1121 context->flags &= ~FLAG_WINDOW;
1122 }
1123 //TODO: Verify behavior for 0x20 case
1124 uint16_t vscroll = 0xFF | (context->regs[REG_SCROLL] & 0x30) << 4;
1125 if (context->double_res) {
1126 vscroll <<= 1;
1127 vscroll |= 1;
1128 } 1128 }
1129 vscroll &= context->vscroll_latch[vsram_off] + line; 1129 vscroll &= context->vscroll_latch[vsram_off] + line;
1130 context->v_offset = vscroll & v_offset_mask; 1130 context->v_offset = vscroll & v_offset_mask;
1131 //printf("%s | line %d, vsram: %d, vscroll: %d, v_offset: %d\n",(vsram_off ? "B" : "A"), line, context->vsram[context->regs[REG_MODE_3] & 0x4 ? column : 0], vscroll, context->v_offset); 1131 //printf("%s | line %d, vsram: %d, vscroll: %d, v_offset: %d\n",(vsram_off ? "B" : "A"), line, context->vsram[context->regs[REG_MODE_3] & 0x4 ? column : 0], vscroll, context->v_offset);
1132 vscroll >>= vscroll_shift; 1132 vscroll >>= vscroll_shift;