void hle_syscall(uint32_t call_id, uint32_t *args) switch(call_id) case 0x1234: // sceDisplaySetFrameBuf g_state.fb_addr = args[0]; g_state.fb_width = args[1]; break; // ... 300+ syscalls
typedef struct uint32_t r[32]; // general purpose regs uint32_t pc; uint32_t hi, lo; // multiply/divide float fpr[32]; // FPU regs uint32_t fcr31; // FPU control // VFPU (vector) – 128 registers float vfpu[128][4]; psp_cpu_t; void cpu_step(psp_cpu_t *cpu) uint32_t instr = mem_read32(cpu->pc); cpu->pc += 4; switch((instr >> 26) & 0x3F) // primary opcode case 0x00: // SPECIAL decode_special(cpu, instr); break; case 0x11: // COP1 (FPU) decode_cop1(cpu, instr); break; case 0x12: // COP2 (VFPU) decode_cop2(cpu, instr); break; // ... other MIPS opcodes pc psp emulator
| Start | End | Purpose | |-------|-----|---------| | 0x00000000 | 0x01FFFFFF | Main RAM (32 MB) | | 0x04000000 | 0x041FFFFF | VRAM (4 MB) | | 0x08000000 | 0x0FFFFFFF | Kernel memory (privileged) | | 0x1C000000 | 0x1FFFFFFF | Hardware registers (memory-mapped I/O) | | 0x88000000 | 0x8FFFFFFF | Uncached RAM mirror | void mix_audio(int16_t *out
| Module | Purpose | Example HLE | |--------|---------|--------------| | scePower | CPU clock, standby | Return success, ignore | | sceDisplay | Framebuffer flip | Swap host window buffers | | sceCtrl | Input reading | Read keyboard/gamepad | | sceIo | File I/O | Map to host filesystem | | sceKernel | Threads/semaphores | Map to host threads | | sceAudio | Sound output | Queue to audio callback | int samples) memset(out
uint8_t *ram = calloc(32, 1024*1024); uint8_t *vram = calloc(4, 1024*1024); uint32_t mem_read32(uint32_t addr) if (addr < 0x02000000) return (uint32_t )(ram + addr); if (addr >= 0x04000000 && addr < 0x04200000) return (uint32_t )(vram + (addr & 0x3FFFFF)); if (addr >= 0x1C000000 && addr < 0x20000000) return hw_read(addr); // handle uncached mirrors (bit 29 cleared) return 0;
PSP's GE is a tile-based deferred renderer similar to PowerVR.
void mix_audio(int16_t *out, int samples) memset(out, 0, samples * 2 * sizeof(int16_t)); for(int ch = 0; ch < 2; ch++) psp_audio_channel *c = &channels[ch]; if(!c->enabled) continue; for(int i = 0; i < samples; i++) int sample = c->read_sample(c); // resample from source buffer out[i*2 + ch] += sample * c->volume / 0x8000;