[nostalgia] Break part of core out into Turbine and TeaGBA libraries

src/turbine/gba/CMakeLists.txt

@@ -0,0 +1,16 @@
+enable_language(CXX ASM)
+set_source_files_properties(turbine.arm.cpp irq.arm.cpp PROPERTIES COMPILE_FLAGS -marm)
+target_sources(
+	Turbine PRIVATE
+		clipboard.cpp
+		gfx.cpp
+		irq.arm.cpp
+		irq.s
+		turbine.arm.cpp
+		turbine.cpp
+)
+
+target_link_libraries(
+	Turbine PUBLIC
+		TeaGBA
+)

src/turbine/gba/clipboard.cpp

@@ -0,0 +1,19 @@
+/*
+ * Copyright 2016 - 2023 Gary Talent (gary@drinkingtea.net). All rights reserved.
+ */
+
+#include <ox/std/string.hpp>
+
+#include <turbine/context.hpp>
+
+namespace turbine {
+
+ox::String getClipboardText(Context&) noexcept {
+	return {};
+}
+
+void setClipboardText(Context&, ox::CRStringView) noexcept {
+
+}
+
+}

src/turbine/gba/context.hpp

@@ -0,0 +1,29 @@
+/*
+ * Copyright 2016 - 2023 Gary Talent (gary@drinkingtea.net). All rights reserved.
+ */
+
+#pragma once
+
+#include <ox/fs/fs.hpp>
+#include <ox/model/desctypes.hpp>
+#include <ox/std/buffer.hpp>
+#include <ox/std/size.hpp>
+
+#include <keel/context.hpp>
+
+#include "../context.hpp"
+
+namespace turbine::gba {
+
+class Context: public turbine::Context {
+	public:
+		bool running = true;
+
+		Context() noexcept = default;
+		Context(Context &other) noexcept = delete;
+		Context(const Context &other) noexcept = delete;
+		Context(const Context &&other) noexcept = delete;
+};
+
+}
+

src/turbine/gba/gfx.cpp

@@ -0,0 +1,42 @@
+/*
+ * Copyright 2016 - 2023 Gary Talent (gary@drinkingtea.net). All rights reserved.
+ */
+
+#include <ox/std/size.hpp>
+#include <ox/std/stringview.hpp>
+
+#include <teagba/addresses.hpp>
+#include <teagba/gfx.hpp>
+#include <teagba/irq.hpp>
+
+#include <turbine/context.hpp>
+
+namespace turbine {
+
+ox::Error initGfx(Context&) noexcept {
+	REG_DISPCTL = teagba::DispCtl_Mode0
+	            | teagba::DispCtl_SpriteMap1D
+	            | teagba::DispCtl_Obj;
+	// tell display to trigger vblank interrupts
+	REG_DISPSTAT = REG_DISPSTAT | teagba::DispStat_irq_vblank;
+	// enable vblank interrupt
+	REG_IE = REG_IE | teagba::Int_vblank;
+	return {};
+}
+
+void setWindowTitle(Context&, ox::CRStringView) noexcept {
+}
+
+int getScreenWidth(Context&) noexcept {
+	return 240;
+}
+
+int getScreenHeight(Context&) noexcept {
+	return 160;
+}
+
+ox::Size getScreenSize(Context&) noexcept {
+	return {240, 160};
+}
+
+}

src/turbine/gba/irq.arm.cpp

@@ -0,0 +1,36 @@
+/*
+ * Copyright 2016 - 2023 Gary Talent (gary@drinkingtea.net). All rights reserved.
+ */
+
+// NOTE: this file is compiled as ARM and not THUMB, so don't but too much in
+// here
+
+#include <teagba/addresses.hpp>
+#include <teagba/gfx.hpp>
+#include <teagba/irq.hpp>
+
+#include "turbine.hpp"
+
+namespace turbine {
+
+volatile gba_timer_t g_timerMs = 0;
+
+}
+
+using namespace turbine;
+
+extern "C" {
+
+void turbine_isr_vblank() {
+	teagba::applySpriteUpdates();
+	if constexpr(config::GbaEventLoopTimerBased) {
+		// disable vblank interrupt until it is needed again
+		REG_IE = REG_IE & ~teagba::Int_vblank;
+	}
+}
+
+void turbine_isr_timer0() {
+	g_timerMs = g_timerMs + 1;
+}
+
+}

src/turbine/gba/irq.s

@@ -0,0 +1,110 @@
+//
+// Copyright 2016 - 2023 gary@drinkingtea.net
+//
+// This Source Code Form is subject to the terms of the Mozilla Public
+// License, v. 2.0. If a copy of the MPL was not distributed with this
+// file, You can obtain one at http://mozilla.org/MPL/2.0/.
+//
+
+.section .iwram, "ax", %progbits
+.arm
+.align
+
+.extern turbine_isr_vblank
+.extern turbine_isr_timer0
+
+.equ REG_IFBIOS,         0x03007ff8
+
+.equ REG_IE,             0x04000200
+.equ REG_IF,             0x04000202
+.equ REG_IME,            0x04000208
+
+.equ Int_vblank,                  1
+.equ Int_hblank,                  2
+.equ Int_vcount,                  4
+.equ Int_timer0,                  8
+.equ Int_timer1,                 16
+.equ Int_timer2,                 32
+.equ Int_timer3,                 64
+.equ Int_serial,                128 // link cable
+.equ Int_dma0,                  256
+.equ Int_dma1,                  512
+.equ Int_dma2,                 1024
+.equ Int_dma3,                 2048
+.equ Int_dma4,                 4096
+.equ Int_dma5,                 8192
+.equ Int_input,               16384 // gamepad
+.equ Int_cart,                32768 // cartridge removed
+
+
+.global isr
+.type isr, %function
+isr:
+	// read IE
+	ldr r0, =#REG_IE
+	ldrh r1, [r0] // r1 becomes IE value
+	ldrh r2, [r0, #2] // r2 becomes IF value
+	and r1, r1, r2 // r1 becomes IE & IF
+	// done with r2 as IF value
+
+	// Acknowledge IRQ in REG_IF
+	strh r1, [r0, #2]
+	ldr r0, =#REG_IFBIOS
+	// Acknowledge IRQ in REG_IFBIOS
+	ldr r2, [r0] // r2 becomes REG_IFBIOS value
+	orr r2, r2, r1
+	str r2, [r0]
+	// done with r2 as IFBIOS value
+	// done with r0 as REG_IFBIOS
+
+	////////////////////////////////////////////////////
+	// Interrupt Table Begin                          //
+	////////////////////////////////////////////////////
+
+	cmp r1, #Int_timer0
+	ldreq r0, =turbine_isr_timer0
+	beq isr_call_handler
+
+	cmp r1, #Int_vblank
+	ldreq r0, =turbine_isr_vblank
+	beq isr_call_handler
+
+	////////////////////////////////////////////////////
+	// Interrupt Table End                            //
+	////////////////////////////////////////////////////
+
+	bx lr
+
+isr_call_handler:
+	// clear IME to disable interrupts
+	ldr r2, =#REG_IME
+	mov r1, #0
+	str r1, [r2]
+
+	// enter system mode
+	mrs r1, cpsr
+	bic r1, r1, #0xDF
+	orr r1, r1, #0x1F
+	msr cpsr, r1
+
+	push {lr}
+	ldr lr, =isr_restore
+	bx r0
+
+isr_restore:
+	pop {lr}
+
+	// re-enter irq mode
+	mrs r0, cpsr
+	bic r0, r0, #0xDF
+	orr r0, r0, #0x92
+	msr cpsr, r0
+
+	// set IME to re-enable interrupts
+	ldr r2, =#REG_IME
+	mov r0, #1
+	str r0, [r2]
+
+	bx lr
+
+// vim: ft=armv4

src/turbine/gba/turbine.arm.cpp

@@ -0,0 +1,41 @@
+/*
+ * Copyright 2016 - 2023 Gary Talent (gary@drinkingtea.net). All rights reserved.
+ */
+
+#include <teagba/addresses.hpp>
+#include <teagba/bios.hpp>
+#include <teagba/irq.hpp>
+
+#include "context.hpp"
+#include "turbine.hpp"
+
+namespace turbine {
+
+extern volatile gba_timer_t g_timerMs;
+gba_timer_t g_wakeupTime;
+
+ox::Error run(Context &ctx) noexcept {
+	g_wakeupTime = 0;
+	const auto gbaCtx = static_cast<gba::Context*>(&ctx);
+	while (gbaCtx->running) {
+		if (g_wakeupTime <= g_timerMs && ctx.updateHandler) {
+			auto sleepTime = ctx.updateHandler(ctx);
+			if (sleepTime >= 0) {
+				g_wakeupTime = g_timerMs + static_cast<unsigned>(sleepTime);
+			} else {
+				g_wakeupTime = ~gba_timer_t(0);
+			}
+		}
+		if constexpr(config::GbaEventLoopTimerBased) {
+			// wait for timer interrupt
+			teagba_intrwait(
+					0,
+					teagba::Int_timer0 | teagba::Int_timer1 | teagba::Int_timer2 | teagba::Int_timer3);
+		} else {
+			teagba_vblankintrwait();
+		}
+	}
+	return {};
+}
+
+}

src/turbine/gba/turbine.cpp

@@ -0,0 +1,80 @@
+/*
+ * Copyright 2016 - 2023 Gary Talent (gary@drinkingtea.net). All rights reserved.
+ */
+
+#include <teagba/addresses.hpp>
+#include <teagba/irq.hpp>
+
+#include <keel/keel.hpp>
+#include <turbine/gfx.hpp>
+
+#include "context.hpp"
+#include "turbine.hpp"
+
+extern "C" void isr();
+
+namespace turbine {
+
+// Timer Consts
+constexpr int NanoSecond = 1000000000;
+constexpr int MilliSecond = 1000;
+constexpr int TicksMs59ns = 65535 - (NanoSecond / MilliSecond) / 59.59;
+
+extern volatile gba_timer_t g_timerMs;
+
+static void initIrq() noexcept {
+	REG_ISR = isr;
+	REG_IME = 1; // enable interrupts
+}
+
+static void initTimer() noexcept {
+	// make timer0 a ~1 millisecond timer
+	REG_TIMER0 = TicksMs59ns;
+	REG_TIMER0CTL = 0b11000000;
+	// enable interrupt for timer0
+	REG_IE = REG_IE | teagba::Int_timer0;
+}
+
+static ox::Result<std::size_t> findPreloadSection() noexcept {
+	// put the header in the wrong order to prevent mistaking this code for the
+	// media section
+	constexpr auto headerP2 = "DER_____________";
+	constexpr auto headerP1 = "KEEL_PRELOAD_HEA";
+	constexpr auto headerP1Len = ox_strlen(headerP2);
+	constexpr auto headerP2Len = ox_strlen(headerP1);
+	constexpr auto headerLen = headerP1Len + headerP2Len;
+	for (auto current = MEM_ROM; current < reinterpret_cast<char*>(0x0a000000); current += headerLen) {
+		if (ox_memcmp(current, headerP1, headerP1Len) == 0 &&
+		    ox_memcmp(current + headerP1Len, headerP2, headerP2Len) == 0) {
+			return reinterpret_cast<std::size_t>(current + headerLen);
+		}
+	}
+	return OxError(1);
+}
+
+ox::Result<ox::UniquePtr<turbine::Context>> init(ox::UPtr<ox::FileSystem> fs, ox::CRStringView appName) noexcept {
+	oxRequireM(ctx, keel::init<gba::Context>(std::move(fs), appName));
+	oxReturnError(findPreloadSection().moveTo(&ctx->preloadSectionOffset));
+	oxReturnError(initGfx(*ctx));
+	initTimer();
+	initIrq();
+	return ox::UPtr<turbine::Context>(std::move(ctx));
+}
+
+void shutdown(Context&) noexcept {
+}
+
+uint64_t ticksMs(Context&) noexcept {
+	return g_timerMs;
+}
+
+bool buttonDown(Context&, Key k) noexcept {
+	return k <= Key::GamePad_L && !(REG_GAMEPAD & (1 << static_cast<int>(k)));
+}
+
+void requestShutdown(Context &ctx) noexcept {
+	const auto gbaCtx = static_cast<gba::Context*>(&ctx);
+	gbaCtx->running = false;
+}
+
+}

src/turbine/gba/turbine.hpp

@@ -0,0 +1,15 @@
+/*
+ * Copyright 2016 - 2023 Gary Talent (gary@drinkingtea.net). All rights reserved.
+ */
+
+#pragma once
+
+#include <ox/std/types.hpp>
+
+#include "../config.hpp"
+
+namespace turbine {
+
+using gba_timer_t = ox::Uint<config::GbaTimerBits>;
+
+}