81 lines
2.2 KiB
C++
81 lines
2.2 KiB
C++
/*
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* Copyright 2016 - 2023 Gary Talent (gary@drinkingtea.net). All rights reserved.
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*/
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#include <teagba/addresses.hpp>
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#include <teagba/irq.hpp>
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#include <keel/keel.hpp>
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#include <turbine/gfx.hpp>
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#include "context.hpp"
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#include "turbine.hpp"
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extern "C" void turbine_isr();
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namespace turbine {
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// Timer Consts
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constexpr int NanoSecond = 1000000000;
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constexpr int MilliSecond = 1000;
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constexpr int TicksMs59ns = 65535 - (NanoSecond / MilliSecond) / 59.59;
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extern volatile gba_timer_t g_timerMs;
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static void initIrq() noexcept {
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REG_ISR = turbine_isr;
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REG_IME = 1; // enable interrupts
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}
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static void initTimer() noexcept {
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// make timer0 a ~1 millisecond timer
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REG_TIMER0 = TicksMs59ns;
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REG_TIMER0CTL = 0b11000000;
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// enable interrupt for timer0
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REG_IE = REG_IE | teagba::Int_timer0;
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}
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static ox::Result<std::size_t> findPreloadSection() noexcept {
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// put the header in the wrong order to prevent mistaking this code for the
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// media section
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constexpr auto headerP2 = "DER_____________";
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constexpr auto headerP1 = "KEEL_PRELOAD_HEA";
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constexpr auto headerP1Len = ox_strlen(headerP2);
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constexpr auto headerP2Len = ox_strlen(headerP1);
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constexpr auto headerLen = headerP1Len + headerP2Len;
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for (auto current = MEM_ROM; current < reinterpret_cast<char*>(0x0a000000); current += headerLen) {
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if (ox_memcmp(current, headerP1, headerP1Len) == 0 &&
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ox_memcmp(current + headerP1Len, headerP2, headerP2Len) == 0) {
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return reinterpret_cast<std::size_t>(current + headerLen);
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}
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}
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return OxError(1);
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}
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ox::Result<ox::UniquePtr<turbine::Context>> init(ox::UPtr<ox::FileSystem> fs, ox::CRStringView appName) noexcept {
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oxRequireM(ctx, keel::init<gba::Context>(std::move(fs), appName));
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oxReturnError(findPreloadSection().moveTo(&ctx->preloadSectionOffset));
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oxReturnError(initGfx(*ctx));
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initTimer();
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initIrq();
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return ox::UPtr<turbine::Context>(std::move(ctx));
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}
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void shutdown(Context&) noexcept {
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}
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uint64_t ticksMs(Context&) noexcept {
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return g_timerMs;
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}
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bool buttonDown(Context&, Key k) noexcept {
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return k <= Key::GamePad_L && !(REG_GAMEPAD & (1 << static_cast<int>(k)));
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}
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void requestShutdown(Context &ctx) noexcept {
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const auto gbaCtx = static_cast<gba::Context*>(&ctx);
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gbaCtx->running = false;
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}
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}
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