Mercurial > repos > blastem
view z80_util.c @ 2069:8e51c0c3f2e3 segacd
Initial attempt at implementing the Sega CD graphics hardware
author | Michael Pavone <pavone@retrodev.com> |
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date | Sun, 30 Jan 2022 19:55:33 -0800 |
parents | 72540af9c90a |
children |
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#include <string.h> void z80_read_8(z80_context *context) { context->cycles += 3 * context->opts->gen.clock_divider; uint8_t *fast = context->fastread[context->scratch1 >> 10]; if (fast) { context->scratch1 = fast[context->scratch1 & 0x3FF]; } else { context->scratch1 = read_byte(context->scratch1, (void **)context->mem_pointers, &context->opts->gen, context); } } void z80_write_8(z80_context *context) { context->cycles += 3 * context->opts->gen.clock_divider; uint8_t *fast = context->fastwrite[context->scratch2 >> 10]; if (fast) { fast[context->scratch2 & 0x3FF] = context->scratch1; } else { write_byte(context->scratch2, context->scratch1, (void **)context->mem_pointers, &context->opts->gen, context); } } void z80_io_read8(z80_context *context) { uint32_t tmp_mask = context->opts->gen.address_mask; memmap_chunk const *tmp_map = context->opts->gen.memmap; uint32_t tmp_chunks = context->opts->gen.memmap_chunks; context->opts->gen.address_mask = context->io_mask; context->opts->gen.memmap = context->io_map; context->opts->gen.memmap_chunks = context->io_chunks; context->cycles += 4 * context->opts->gen.clock_divider; context->scratch1 = read_byte(context->scratch1, (void **)context->mem_pointers, &context->opts->gen, context); context->opts->gen.address_mask = tmp_mask; context->opts->gen.memmap = tmp_map; context->opts->gen.memmap_chunks = tmp_chunks; } void z80_io_write8(z80_context *context) { uint32_t tmp_mask = context->opts->gen.address_mask; memmap_chunk const *tmp_map = context->opts->gen.memmap; uint32_t tmp_chunks = context->opts->gen.memmap_chunks; context->opts->gen.address_mask = context->io_mask; context->opts->gen.memmap = context->io_map; context->opts->gen.memmap_chunks = context->io_chunks; context->cycles += 4 * context->opts->gen.clock_divider; write_byte(context->scratch2, context->scratch1, (void **)context->mem_pointers, &context->opts->gen, context); context->opts->gen.address_mask = tmp_mask; context->opts->gen.memmap = tmp_map; context->opts->gen.memmap_chunks = tmp_chunks; } //quick hack until I get a chance to change which init method these get passed to static memmap_chunk const * tmp_io_chunks; static uint32_t tmp_num_io_chunks, tmp_io_mask; void init_z80_opts(z80_options * options, memmap_chunk const * chunks, uint32_t num_chunks, memmap_chunk const * io_chunks, uint32_t num_io_chunks, uint32_t clock_divider, uint32_t io_address_mask) { memset(options, 0, sizeof(*options)); options->gen.memmap = chunks; options->gen.memmap_chunks = num_chunks; options->gen.address_mask = 0xFFFF; options->gen.max_address = 0xFFFF; options->gen.clock_divider = clock_divider; tmp_io_chunks = io_chunks; tmp_num_io_chunks = num_io_chunks; tmp_io_mask = io_address_mask; } void z80_options_free(z80_options *opts) { free(opts); } z80_context * init_z80_context(z80_options *options) { z80_context *context = calloc(1, sizeof(z80_context)); context->opts = options; context->io_map = (memmap_chunk *)tmp_io_chunks; context->io_chunks = tmp_num_io_chunks; context->io_mask = tmp_io_mask; context->int_cycle = context->int_end_cycle = context->nmi_cycle = 0xFFFFFFFFU; z80_invalidate_code_range(context, 0, 0xFFFF); return context; } void z80_sync_cycle(z80_context *context, uint32_t target_cycle) { if (context->iff1 && context->int_cycle < target_cycle) { if (context->cycles > context->int_end_cycle) { context->int_cycle = 0xFFFFFFFFU; } else { target_cycle = context->int_cycle; } }; if (context->nmi_cycle < target_cycle) { target_cycle = context->nmi_cycle; } context->sync_cycle = target_cycle; } void z80_run(z80_context *context, uint32_t target_cycle) { if (context->reset || context->busack) { context->cycles = target_cycle; } else if (target_cycle > context->cycles) { if (context->busreq) { //busreq is sampled at the end of an m-cycle //we can approximate that by running for a single m-cycle after a bus request target_cycle = context->cycles + 4 * context->opts->gen.clock_divider; } z80_execute(context, target_cycle); if (context->busreq) { context->busack = 1; } } } void z80_assert_reset(z80_context * context, uint32_t cycle) { z80_run(context, cycle); context->reset = 1; } void z80_clear_reset(z80_context * context, uint32_t cycle) { z80_run(context, cycle); if (context->reset) { context->imode = 0; context->iff1 = context->iff2 = 0; context->pc = 0; context->reset = 0; if (context->busreq) { //TODO: Figure out appropriate delay context->busack = 1; } } } #define MAX_MCYCLE_LENGTH 6 void z80_assert_busreq(z80_context * context, uint32_t cycle) { z80_run(context, cycle); context->busreq = 1; //this is an imperfect aproximation since most M-cycles take less tstates than the max //and a short 3-tstate m-cycle can take an unbounded number due to wait states if (context->cycles - cycle > MAX_MCYCLE_LENGTH * context->opts->gen.clock_divider) { context->busack = 1; } } void z80_clear_busreq(z80_context * context, uint32_t cycle) { z80_run(context, cycle); context->busreq = 0; context->busack = 0; //there appears to be at least a 1 Z80 cycle delay between busreq //being released and resumption of execution context->cycles += context->opts->gen.clock_divider; } void z80_assert_nmi(z80_context *context, uint32_t cycle) { context->nmi_cycle = cycle; } uint8_t z80_get_busack(z80_context * context, uint32_t cycle) { z80_run(context, cycle); return context->busack; } void z80_invalidate_code_range(z80_context *context, uint32_t startA, uint32_t endA) { for(startA &= ~0x3FF; startA < endA; startA += 1024) { uint8_t *start = get_native_pointer(startA, (void**)context->mem_pointers, &context->opts->gen); if (start) { uint8_t *end = get_native_pointer(startA + 1023, (void**)context->mem_pointers, &context->opts->gen); if (!end || end - start != 1023) { start = NULL; } } context->fastread[startA >> 10] = start; start = get_native_write_pointer(startA, (void**)context->mem_pointers, &context->opts->gen); if (start) { uint8_t *end = get_native_write_pointer(startA + 1023, (void**)context->mem_pointers, &context->opts->gen); if (!end || end - start != 1023) { start = NULL; } } context->fastwrite[startA >> 10] = start; } } void z80_adjust_cycles(z80_context * context, uint32_t deduction) { context->cycles -= deduction; if (context->int_cycle != 0xFFFFFFFFU) { if (context->int_cycle > deduction) { context->int_cycle -= deduction; } else { context->int_cycle = 0; } } if (context->int_end_cycle != 0xFFFFFFFFU) { if (context->int_end_cycle > deduction) { context->int_end_cycle -= deduction; } else { context->int_end_cycle = 0; } } if (context->nmi_cycle != 0xFFFFFFFFU) { if (context->nmi_cycle > deduction) { context->nmi_cycle -= deduction; } else { context->nmi_cycle = 0; } } } void z80_serialize(z80_context *context, serialize_buffer *buf) { save_int8(buf, context->main[1]);//C save_int8(buf, context->main[0]);//B save_int8(buf, context->main[3]);//E save_int8(buf, context->main[2]);//D save_int8(buf, context->main[5]);//L save_int8(buf, context->main[4]);//H save_int8(buf, context->ix);//IXL save_int8(buf, context->ix >> 8);//IXH save_int8(buf, context->iy);//IYL save_int8(buf, context->iy >> 8);//IYH save_int8(buf, context->i); save_int8(buf, (context->rhigh & 0x80) | (context->r & 0x7F)); save_int8(buf, context->main[7]);//A uint8_t f = context->last_flag_result & 0xA8 | (context->zflag ? 0x40 : 0) | (context->chflags & 8 ? 0x10 : 0) | (context->pvflag ? 4 : 0) | (context->nflag ? 2 : 0) | (context->chflags & 0x80 ? 1 : 0); save_int8(buf, f); save_int8(buf, context->alt[1]);//C save_int8(buf, context->alt[0]);//B save_int8(buf, context->alt[3]);//E save_int8(buf, context->alt[2]);//D save_int8(buf, context->alt[5]);//L save_int8(buf, context->alt[4]);//H save_int8(buf, 0);//non-existant alt ixl save_int8(buf, 0);//non-existant alt ixh save_int8(buf, 0);//non-existant alt iyl save_int8(buf, 0);//non-existant alt iyh save_int8(buf, 0);//non-existant alt i save_int8(buf, 0);//non-existant alt r save_int8(buf, context->alt[7]);//A save_int8(buf, context->alt[6]);//F save_int16(buf, context->pc); save_int16(buf, context->sp); save_int8(buf, context->imode); save_int8(buf, context->iff1); save_int8(buf, context->iff2); uint8_t is_nmi = context->nmi_cycle != 0xFFFFFFFF && (context->nmi_cycle < context->int_cycle || !context->iff1); save_int8(buf, is_nmi);//int_is_nmi save_int8(buf, context->busack); save_int32(buf, context->cycles); save_int32(buf, is_nmi ? context->nmi_cycle : context->int_cycle);//int_cycle save_int32(buf, 0);//int_enable_cycle save_int32(buf, context->int_cycle); save_int32(buf, context->int_end_cycle); save_int32(buf, context->nmi_cycle); } void z80_deserialize(deserialize_buffer *buf, void *vcontext) { z80_context *context = vcontext; context->main[1] = load_int8(buf);//C context->main[0] = load_int8(buf);//B context->main[3] = load_int8(buf);//E context->main[2] = load_int8(buf);//D context->main[5] = load_int8(buf);//L context->main[4] = load_int8(buf);//H context->ix = load_int8(buf);//IXL context->ix |= load_int8(buf) << 8;//IXH context->iy = load_int8(buf);//IYL context->iy |= load_int8(buf) << 8;//IYH context->i = load_int8(buf); context->r = load_int8(buf); context->rhigh = context->r & 0x80; context->main[7] = load_int8(buf);//A context->last_flag_result = load_int8(buf); context->zflag = context->last_flag_result & 0x40; context->chflags = context->last_flag_result & 0x10 ? 8 : 0; context->pvflag = context->last_flag_result & 4; context->nflag = context->last_flag_result & 2; context->chflags |= context->last_flag_result & 1 ? 0x80 : 0; context->alt[1] = load_int8(buf);//C context->alt[0] = load_int8(buf);//B context->alt[3] = load_int8(buf);//E context->alt[2] = load_int8(buf);//D context->alt[5] = load_int8(buf);//L context->alt[4] = load_int8(buf);//H load_int8(buf);//non-existant alt ixl load_int8(buf);//non-existant alt ixh load_int8(buf);//non-existant alt iyl load_int8(buf);//non-existant alt iyh load_int8(buf);//non-existant alt i load_int8(buf);//non-existant alt r context->alt[7] = load_int8(buf);//A context->alt[6] = load_int8(buf);//F context->pc = load_int16(buf); context->sp = load_int16(buf); context->imode = load_int8(buf); context->iff1 = load_int8(buf); context->iff2 = load_int8(buf); load_int8(buf);//int_is_nmi context->busack = load_int8(buf); context->cycles = load_int32(buf); load_int32(buf);//int_cycle load_int32(buf);//int_enable_cycle context->int_cycle = load_int32(buf); context->int_end_cycle = load_int32(buf); context->nmi_cycle = load_int32(buf); } void zinsert_breakpoint(z80_context * context, uint16_t address, uint8_t * bp_handler) { } void zremove_breakpoint(z80_context * context, uint16_t address) { }