105 lines
2.5 KiB
C
105 lines
2.5 KiB
C
#include <cpu.h>
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#include <emu.h>
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#include <bus.h>
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//process CPU instructions...
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void cpu_set_flags(cpu_context *ctx, u8 z, u8 n, u8 h, u8 c){
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if (z != -1){
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BIT_SET(ctx->regs.f, 7, z)
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}
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if (n != -1){
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BIT_SET(ctx->regs.f, 6, n)
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}
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if (h != -1){
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BIT_SET(ctx->regs.f, 5, h)
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}
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if (c != -1){
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BIT_SET(ctx->regs.f, 4, c)
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}
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}
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static void proc_none(cpu_context *ctx) {
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printf("INVALID INSTRUCTION!\n");
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exit(-7);
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}
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static void proc_nop(cpu_context *ctx) {
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}
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static void proc_ldh(cpu_context *ctx) {
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if (!ctx->dest_is_mem) {
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cpu_set_reg(ctx->cur_inst->reg_1, bus_read(0XFF00 | ctx->fetched_data));
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} else {
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bus_write(0xFF00 | ctx->mem_dest, ctx->cur_inst->reg_2);
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}
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emu_cycles(1);
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}
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static void proc_xor(cpu_context *ctx) {
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ctx->regs.a ^= ctx->fetched_data & 0XFF;
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cpu_set_flags(ctx, ctx->regs.a == 0, 0, 0, 0);
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}
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static void proc_di(cpu_context *ctx) {
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ctx->int_master_enabled = false;
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}
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static void proc_ld(cpu_context *ctx) {
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if(ctx->dest_is_mem) {
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if(ctx->cur_inst->reg_2 >= RT_AF) {
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bus_write16(ctx->mem_dest, ctx->fetched_data);
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emu_cycles(1);
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} else {
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bus_write(ctx->mem_dest, ctx->fetched_data);
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emu_cycles(1);
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}
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return;
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}
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if (ctx->cur_inst->mode == AM_HL_SPR) {
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u8 hflag = (cpu_read_reg(ctx->cur_inst->reg_2) & 0xF) + (ctx->fetched_data & 0xF) >= 0x10;
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u8 cflag = (cpu_read_reg(ctx->cur_inst->reg_2) & 0xFF) + (ctx->fetched_data & 0xFF) >= 0x100;
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cpu_set_flags(ctx, 0, 0, hflag, cflag);
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cpu_set_reg(ctx->cur_inst->reg_1, cpu_read_reg(ctx->cur_inst->reg_2) + (char)ctx->fetched_data);
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}
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cpu_set_reg(ctx->cur_inst->reg_1, ctx->fetched_data);
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}
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static bool check_condition(cpu_context *ctx) {
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bool z = CPU_FLAG_Z;
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bool c = CPU_FLAG_C;
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switch(ctx->cur_inst->cond) {
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case CT_NONE: return true;
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case CT_C: return c;
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case CT_NC: return !c;
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case CT_Z: return z;
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case CT_NZ: return !z;
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}
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return false;
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}
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static void proc_jp(cpu_context *ctx) {
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if (check_condition(ctx)) {
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ctx->regs.pc = ctx->fetched_data;
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emu_cycles(1);
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}
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}
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IN_PROC processors[] = {
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[IN_NONE] = proc_none,
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[IN_NOP] = proc_nop,
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[IN_LD] = proc_ld,
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[IN_JP] = proc_jp,
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[IN_DI] = proc_di,
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[IN_XOR] = proc_xor,
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[IN_LDH] = proc_ldh
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};
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IN_PROC inst_get_processor(in_type type) {
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return processors[type];
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} |