Zelda64Recomp/src/recomp/dp.cpp

#include "recomp.h"

enum class RDPStatusBit {
	XbusDmem = 0,
	Freeze = 1,
	Flush = 2,
	CommandBusy = 6,
	BufferReady = 7,
	DmaBusy = 8,
	EndValid = 9,
	StartValid = 10,
};

constexpr void update_bit(uint32_t& state, uint32_t flags, RDPStatusBit bit) {
	int set_bit_pos = (int)bit * 2 + 0;
	int reset_bit_pos = (int)bit * 2 + 1;
	bool set = (flags & (1U << set_bit_pos)) != 0;
	bool reset = (flags & (1U << reset_bit_pos)) != 0;

	if (set ^ reset) {
		if (set) {
			state |= (1U << (int)bit);
		}
		else {
			state &= ~(1U << (int)bit);
		}
	}
}

uint32_t rdp_state = 1 << (int)RDPStatusBit::BufferReady;

extern "C" void osDpSetNextBuffer_recomp(uint8_t* rdram, recomp_context* ctx) {
    assert(false);
}

extern "C" void osDpGetStatus_recomp(uint8_t* rdram, recomp_context* ctx) {
	ctx->r2 = rdp_state;
}

extern "C" void osDpSetStatus_recomp(uint8_t* rdram, recomp_context* ctx) {
	update_bit(rdp_state, ctx->r4, RDPStatusBit::XbusDmem);
	update_bit(rdp_state, ctx->r4, RDPStatusBit::Freeze);
	update_bit(rdp_state, ctx->r4, RDPStatusBit::Flush);
}