ppu.c

#include "global.h"
#include "rsp.h"
#include "hwdefs.h"
#include "config.h"

#include "logger.h"

#include <libdragon.h>

typedef struct { // Extends ppuInterface
    union {
        u32 Settings[8];
        struct {
            uintptr_t VRamAddress;
            uintptr_t HRamAddress;
            uintptr_t OAMAddress;
            uintptr_t OutBuffer;
            Rectangle Screen;
            uintptr_t FrameBuffer[2];
        };
    };
} PpuInterface;

extern void* __safe_buffer[];

PpuInterface* ppuInterface;

void ppuInit(PlayerState* state) {
    Rectangle screen = {};
    getScreenPosition(0, &screen);

    ppuInterface = allocRspInterface(sizeof(PpuInterface));

    ppuInterface->Screen = (Rectangle) { screen.Left, screen.Top, 320, 2 };

    ppuInterface->VRamAddress = (uintptr_t) state->EmulationState.VRAM;
    ppuInterface->HRamAddress = (uintptr_t) state->EmulationState.HRAM;
    ppuInterface->OAMAddress = (uintptr_t) state->EmulationState.OAM;
    ppuInterface->OutBuffer = (uintptr_t)state->EmulationState.TextureBuffer;
    ppuInterface->FrameBuffer[0] = (uintptr_t) (__safe_buffer[0]);
    ppuInterface->FrameBuffer[1] = (uintptr_t) (__safe_buffer[1]);

    data_cache_hit_writeback(ppuInterface, sizeof(PpuInterface));

    prepareMicrocode(UCODE_DMG_PPU);

    setDataReady(false);
    run_ucode();
}

void ppuStep(PlayerState* state) {
    if (state->EmulationState.lcd_entered_hblank) {

        if (state->EmulationState.CurrentLine >= GB_LCD_HEIGHT) { // VBlank
            return;
        }

        #ifdef FRAMES_TO_SKIP
            if ((state->Meta.FrameCount + 1) % (FRAMES_TO_SKIP + 1)) {
                return;
            }
        #endif

        data_cache_hit_writeback(state->EmulationState.OAM, OAM_SIZE);
        data_cache_hit_writeback(state->EmulationState.HRAM, HRAM_SIZE);
        if (state->EmulationState.isVramDirty) {
            data_cache_hit_writeback(state->EmulationState.VRAM, VRAM_BANK_SIZE);
            state->EmulationState.isVramDirty = false;
        }

        // Let the RSP finish its current job.
        #ifdef LOCK_CPU_TO_PPU
            while(isRspBusy());
        #endif
        setDataReady(true);
    }
}