diff options
Diffstat (limited to 'vdp.c')
| -rw-r--r-- | vdp.c | 52 |
1 files changed, 34 insertions, 18 deletions
@@ -2140,6 +2140,39 @@ void vdp_run_dma_done(vdp_context * context, uint32_t target_cycles) } } +static uint16_t get_ext_vcounter(vdp_context *context) +{ + uint16_t line= context->vcounter & 0xFF; + if (context->double_res) { + line <<= 1; + if (line & 0x100) { + line |= 1; + } + } + return line << 8; +} + +void vdp_latch_hv(vdp_context *context) +{ + context->hv_latch = context->hslot | get_ext_vcounter(context); +} + +uint16_t vdp_hv_counter_read(vdp_context * context) +{ + if ((context->regs[REG_MODE_2] & BIT_MODE_5) && (context->regs[REG_MODE_1] & BIT_HVC_LATCH)) { + return context->hv_latch; + } + uint16_t hv; + if (context->regs[REG_MODE_2] & BIT_MODE_5) { + hv = context->hslot; + } else { + hv = context->hv_latch & 0xFF; + } + hv |= get_ext_vcounter(context); + + return hv; +} + int vdp_control_port_write(vdp_context * context, uint16_t value) { //printf("control port write: %X at %d\n", value, context->cycles); @@ -2184,7 +2217,7 @@ int vdp_control_port_write(vdp_context * context, uint16_t value) if (reg < (mode_5 ? VDP_REGS : 0xB)) { //printf("register %d set to %X\n", reg, value & 0xFF); if (reg == REG_MODE_1 && (value & BIT_HVC_LATCH) && !(context->regs[reg] & BIT_HVC_LATCH)) { - context->hv_latch = vdp_hv_counter_read(context); + vdp_latch_hv(context); } if (reg == REG_BG_COLOR) { value &= 0x3F; @@ -2388,23 +2421,6 @@ uint8_t vdp_data_port_read_pbc(vdp_context * context) return context->prefetch; } -uint16_t vdp_hv_counter_read(vdp_context * context) -{ - if ((context->regs[REG_MODE_2] & BIT_MODE_5) && (context->regs[REG_MODE_1] & BIT_HVC_LATCH)) { - return context->hv_latch; - } - uint32_t line= context->vcounter & 0xFF; - uint32_t linecyc = context->hslot; - linecyc &= 0xFF; - if (context->double_res) { - line <<= 1; - if (line & 0x100) { - line |= 1; - } - } - return (line << 8) | linecyc; -} - uint16_t vdp_test_port_read(vdp_context * context) { //TODO: Find out what actually gets returned here |