Implement most cpu op-codes
This commit is contained in:
parent
8c29047ff3
commit
dff3495087
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@ -8,13 +8,13 @@
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typedef uint32_t u32;
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typedef uint16_t u16;
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typedef uint8_t u8;
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typedef int64_t i64;
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typedef int32_t i32;
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typedef int16_t i16;
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typedef float f32;
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typedef unsigned char u8;
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#define INVALID_CODE_PATH 0
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@ -88,7 +88,7 @@ inline FILE_SCOPE void common_wstrcat(const wchar_t *a, i32 lenA,
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ASSERT(outIndex <= outLen);
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}
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inline FILE_SCOPE wchar_t common_wcharAsciiToLowercase(wchar_t character)
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inline FILE_SCOPE wchar_t common_wchar_ascii_to_lower(wchar_t character)
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{
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if (character >= L'A' && character <= L'Z')
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{
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416
src/dchip8.cpp
416
src/dchip8.cpp
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@ -1,12 +1,71 @@
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#include "common.h"
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#include "dchip8_platform.h"
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void dchip8_update(PlatformRenderBuffer *renderBuffer, PlatformInput *input)
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typedef struct Chip8CPU
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{
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union {
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u8 registerArray[16];
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struct
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{
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u8 V0;
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u8 V1;
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u8 V2;
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u8 V3;
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u8 V4;
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u8 V5;
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u8 V6;
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u8 V7;
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u8 V8;
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u8 V9;
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u8 VA;
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u8 VB;
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u8 VC;
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u8 VD;
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u8 VE;
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u8 VF;
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};
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};
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// NOTE: Timer that count at 60hz and when set above 0 will count down to 0.
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union {
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u8 dt;
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u8 delayTimer;
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};
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union {
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u8 st;
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u8 soundTimer;
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};
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// NOTE: Maximum value is 0xFFF, or 4095 or 12 bits
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union {
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u16 I;
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u16 indexRegister;
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};
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// NOTE: Maximum value is 0xFFF, or 4095 or 12 bits
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u16 programCounter;
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u8 stackPointer;
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u16 stack[16];
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bool isInit;
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} Chip8CPU;
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FILE_SCOPE Chip8CPU cpu;
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FILE_SCOPE u16 opCodes[35];
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void dchip8_update(PlatformRenderBuffer renderBuffer, PlatformInput input,
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PlatformMemory memory)
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{
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ASSERT(indexRegister >= 0 && indexRegister <= 0xFFF);
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ASSERT(programCounter >= 0 && programCounter <= 0xFFF);
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ASSERT(renderBuffer.bytesPerPixel == 4);
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const i32 numPixels = renderBuffer->width * renderBuffer->height;
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u32 *bitmapBuffer = (u32 *)renderBuffer->memory;
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const i32 numPixels = renderBuffer.width * renderBuffer.height;
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u32 *bitmapBuffer = (u32 *)renderBuffer.memory;
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for (i32 i = 0; i < numPixels; i++)
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{
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// NOTE: Win32 AlphaBlend requires the RGB components to be
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@ -24,4 +83,355 @@ void dchip8_update(PlatformRenderBuffer *renderBuffer, PlatformInput *input)
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u32 color = (a << 24) | (r << 16) | (g << 8) | (b << 0);
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bitmapBuffer[i] = color;
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}
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if (!cpu.isInit)
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{
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ASSERT(memory.permanentMemSize == (4096 / 4));
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cpu.isInit = true;
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// NOTE: Everything before 0x200 is reserved for the actual emulator
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const u32 INIT_ADDRESS = 0x200;
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cpu.programCounter = INIT_ADDRESS;
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cpu.I = 0;
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cpu.stackPointer = 0;
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}
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u8 *mainMem = (u8 *)memory.permanentMem;
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u8 opHighByte = mainMem[cpu.programCounter++];
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u8 opLowByte = mainMem[cpu.programCounter++];
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u8 opFirstNibble = (opHighByte & 0xF0);
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switch (opFirstNibble)
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{
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case 0x00:
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{
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// CLS - 00E0 - Clear the display
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if (opLowByte == 0xE0)
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{
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}
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// RET - 00EE - Return from subroutine
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else if (opLowByte == 0xEE)
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{
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cpu.programCounter = cpu.stack[cpu.stackPointer--];
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}
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}
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break;
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case 0x10:
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case 0x20:
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{
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u16 loc = ((0x0F & opHighByte) << 8) | (0xFF & opLowByte);
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ASSERT(loc <= 0x0FFF);
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// JP addr - 1nnn - Jump to location nnn
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if (opFirstNibble == 0x10)
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{
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// NOTE: Jump to loc, as per below
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}
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// Call addr - 2nnn - Call subroutine at nnn
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else
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{
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ASSERT(opFirstNibble == 0x20);
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cpu.stackPointer++;
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ASSERT(cpu.stackPointer < ARRAY_COUNT(cpu.stack));
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cpu.stack[cpu.stackPointer] = cpu.programCounter;
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}
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cpu.programCounter = loc;
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}
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break;
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case 0x30:
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case 0x40:
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{
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u8 regNum = (0x0F & opHighByte);
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ASSERT(regNum < ARRAY_COUNT(cpu.registerArray));
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u8 valToCheck = opLowByte;
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// SE Vx, byte - 3xkk - Skip next instruction if Vx == kk
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if (opFirstNibble == 0x30)
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{
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if (cpu.registerArray[regNum] == valToCheck)
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cpu.programCounter += 2;
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}
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// SNE Vx, byte - 4xkk - Skip next instruction if Vx == kk
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else
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{
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ASSERT(opFirstNibble == 0x40);
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if (cpu.registerArray[regNum] != valToCheck)
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cpu.programCounter += 2;
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}
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}
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break;
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// SE Vx, Vy - 5xy0 - Skip next instruction if Vx = Vy
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case 0x50:
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{
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u8 firstRegNum = (0x0F & opHighByte);
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ASSERT(firstRegNum < ARRAY_COUNT(cpu.registerArray));
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u8 secondRegNum = (0xF0 & opLowByte);
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ASSERT(secondRegNum < ARRAY_COUNT(cpu.registerArray));
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if (cpu.registerArray[firstRegNum] ==
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cpu.registerArray[secondRegNum])
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{
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cpu.programCounter++;
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}
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}
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break;
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case 0x60:
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case 0x70:
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{
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u8 regNum = (0x0F & opHighByte);
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ASSERT(regNum < ARRAY_COUNT(cpu.registerArray));
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u8 valToOperateOn = opLowByte;
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// LD Vx, byte - 6xkk - Set Vx = kk
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if (opFirstNibble == 0x60)
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{
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cpu.registerArray[regNum] = valToOperateOn;
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}
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// ADD Vx, byte - 7xkk - Set Vx = Vx + kk
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else
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{
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ASSERT(opFirstNibble == 0x70);
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cpu.registerArray[regNum] += valToOperateOn;
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}
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}
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break;
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case 0x80:
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{
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u8 firstRegNum = (0x0F & opHighByte);
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ASSERT(firstRegNum < ARRAY_COUNT(cpu.registerArray));
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u8 secondRegNum = (0xF0 & opLowByte);
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ASSERT(secondRegNum < ARRAY_COUNT(cpu.registerArray));
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u8 *vx = &cpu.registerArray[firstRegNum];
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u8 *vy = &cpu.registerArray[secondRegNum];
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// LD Vx, Vy - 8xy0 - Set Vx = Vy
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if (opLowByte == 0x00)
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{
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*vx = *vy;
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}
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// OR Vx, Vy - 8xy1 - Set Vx = Vx OR Vy
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else if (opLowByte == 0x01)
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{
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u8 result = (*vx | *vy);
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*vx = result;
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}
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// AND Vx, Vy - 8xy2 - Set Vx = Vx AND Vy
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else if (opLowByte == 0x02)
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{
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u8 result = (*vx & *vy);
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*vx = result;
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}
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// XOR Vx, Vy - 8xy3 - Set Vx = Vx XOR Vy
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else if (opLowByte == 0x03)
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{
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u8 result = (*vx & *vy);
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*vx = result;
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}
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// ADD Vx, Vy - 8xy4 - Set Vx = Vx + Vy, set VF = carry
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else if (opLowByte == 0x04)
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{
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u16 result = (*vx + *vy);
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*vx = (u8)result;
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if (result > 255) cpu.VF = (result > 255) ? 1 : 0;
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}
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// SUB Vx, Vy - 8xy5 - Set Vx = Vx - Vy, set VF = NOT borrow
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else if (opLowByte == 0x05)
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{
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if (*vx > *vy)
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cpu.VF = 1;
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else
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cpu.VF = 0;
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*vx -= *vy;
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}
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// SHR Vx {, Vy} - 8xy6 - Set Vx = Vx SHR 1
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else if (opLowByte == 0x06)
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{
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if (*vx & 1)
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cpu.VF = 1;
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else
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cpu.VF = 0;
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*vx >>= 1;
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}
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// SUBN Vx {, Vy} - 8xy7 - Set Vx = Vy - Vx, set VF = NOT borrow
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else if (opLowByte == 0x07)
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{
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if (*vy > *vx)
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cpu.VF = 1;
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else
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cpu.VF = 0;
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*vx = *vy - *vx;
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}
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// SHL Vx {, Vy} - 8xyE - Set Vx = SHL 1
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else
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{
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ASSERT(opLowByte == 0x0E);
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if ((*vx >> 7) == 1)
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cpu.VF = 1;
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else
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cpu.VF = 0;
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*vx <<= 1;
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}
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}
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break;
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// SNE Vx, Vy - 9xy0 - Skip next instruction if Vx != Vy
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case 0x90:
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{
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u8 firstRegNum = (0x0F & opHighByte);
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ASSERT(firstRegNum < ARRAY_COUNT(cpu.registerArray));
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u8 secondRegNum = (0xF0 & opLowByte);
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ASSERT(secondRegNum < ARRAY_COUNT(cpu.registerArray));
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u8 *vx = &cpu.registerArray[firstRegNum];
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u8 *vy = &cpu.registerArray[secondRegNum];
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if (*vx != *vy) cpu.programCounter+= 2;
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}
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break;
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// LD I, addr - Annn - Set I = nnn
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case 0xA0:
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{
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u8 valToSet = opLowByte;
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cpu.indexRegister = valToSet;
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}
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break;
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// JP V0, addr - Bnnn - Jump to location (nnn + V0)
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case 0xB0:
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{
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u8 addr = opLowByte + cpu.V0;
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cpu.programCounter = addr;
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}
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break;
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// RND Vx, byte - Cxkk - Set Vx = random byte AND kk
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case 0xC0:
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{
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u8 firstRegNum = (0x0F & opHighByte);
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ASSERT(firstRegNum < ARRAY_COUNT(cpu.registerArray));
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u8 andBits = opLowByte;
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u8 *vx = &cpu.registerArray[firstRegNum];
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// TODO(doyle): Random umber
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*vx = (28 & opLowByte);
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}
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break;
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// DRW Vx, Vy, nibble - Dxyn - Display n-byte sprite starting at mem
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// location I at (Vx, Vy), set VF = collision
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case 0xD0:
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{
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// TODO(doyle): Implement drawing
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}
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break;
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case 0xE0:
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{
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// TODO(doyle): Implement key checks
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u8 checkKey = (0x0F & opHighByte);
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// SKP Vx - Ex9E - Skip next instruction if key with the value of Vx
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// is pressed
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bool skipNextInstruction = false;
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if (opLowByte == 0x9E)
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{
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}
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// SKNP Vx - ExA1 - Skip next instruction if key with the value of
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// Vx is not pressed
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else
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{
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ASSERT(opLowByte == 0xA1);
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}
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if (skipNextInstruction) cpu.programCounter += 2;
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}
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break;
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case 0xF0:
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{
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u8 regNum = (0x0F & opHighByte);
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ASSERT(regNum < ARRAY_COUNT(cpu.registerArray));
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u8 *vx = &cpu.registerArray[regNum];
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// LD Vx, DT - Fx07 - Set Vx = delay timer value
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if (opLowByte == 0x07)
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{
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*vx = cpu.delayTimer;
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}
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// LD Vx, K - Fx0A - Wait for a key press, store the value of the
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// key in Vx
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else if (opLowByte == 0x0A)
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{
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}
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// LD DT, Vx - Fx15 - Set delay timer = Vx
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else if (opLowByte == 0x15)
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{
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cpu.delayTimer = *vx;
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}
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// LD ST, Vx - Fx18 - Set sound timer = Vx
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else if (opLowByte == 0x18)
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{
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cpu.soundTimer = *vx;
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}
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// ADD I, Vx - Fx1E - Set I = I + Vx
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else if (opLowByte == 0x1E)
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{
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cpu.indexRegister += *vx;
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}
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// LD F, Vx - Fx29 - Set I = location of sprite for digit Vx
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else if (opLowByte == 0x29)
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{
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// TODO: Implement
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}
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// LD B, Vx - Fx33 - Store BCD representations of Vx in memory
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// locations I, I+1 and I+2
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else if (opLowByte == 0x33)
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{
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}
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// LD [I], Vx - Fx55 - Store register V0 through Vx in memory
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// starting at location I.
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else if (opLowByte == 0x55)
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{
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for (u32 regIndex = 0; regIndex <= regNum; regIndex++)
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{
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u32 mem_offset = regIndex;
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mainMem[cpu.indexRegister + mem_offset] =
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cpu.registerArray[regIndex];
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}
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}
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// LD [I], Vx - Fx65 - Read registers V0 through Vx from memory
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// starting at location I.
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else
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{
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ASSERT(opLowByte == 0x65);
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for (u32 regIndex = 0; regIndex <= regNum; regIndex++)
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{
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u32 mem_offset = regIndex;
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cpu.registerArray[regIndex] =
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mainMem[cpu.indexRegister + mem_offset];
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}
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}
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}
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break;
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};
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}
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@ -3,6 +3,7 @@
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#include "dchip8_platform.h"
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void dchip8_update(PlatformRenderBuffer *renderBuffer, PlatformInput *input);
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void dchip8_update(PlatformRenderBuffer renderBuffer, PlatformInput input,
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PlatformMemory memory);
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#endif
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@ -29,6 +29,8 @@ typedef struct KeyState
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typedef struct PlatformInput
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{
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f32 deltaForFrame;
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union {
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KeyState key[key_count];
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struct
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@ -42,4 +44,13 @@ typedef struct PlatformInput
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};
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} PlatformInput;
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typedef struct PlatformMemory
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{
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void *permanentMem;
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u32 permanentMemSize;
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void *transientMem;
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u32 transientMemSize;
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} PlatformMemory;
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#endif
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@ -140,6 +140,9 @@ FILE_SCOPE void win32_process_messages(HWND window, PlatformInput *input)
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int WINAPI WinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance,
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LPSTR lpCmdLine, int nShowCmd)
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{
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////////////////////////////////////////////////////////////////////////////
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// Initialise Win32 Window
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////////////////////////////////////////////////////////////////////////////
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WNDCLASSEX wc =
|
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{
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sizeof(WNDCLASSEX),
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|
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@ -224,6 +227,11 @@ int WINAPI WinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance,
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////////////////////////////////////////////////////////////////////////////
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// Update Loop
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////////////////////////////////////////////////////////////////////////////
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u8 stackMemory[4096] = {};
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PlatformMemory platformMemory = {};
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platformMemory.permanentMem = &stackMemory;
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platformMemory.permanentMemSize = (ARRAY_COUNT(stackMemory) / 4);
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QueryPerformanceFrequency(&globalQueryPerformanceFrequency);
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const f32 TARGET_FRAMES_PER_S = 60.0f;
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f32 targetSecondsPerFrame = 1 / TARGET_FRAMES_PER_S;
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|
|
@ -237,14 +245,15 @@ int WINAPI WinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance,
|
|||
////////////////////////////////////////////////////////////////////////
|
||||
LARGE_INTEGER startFrameTime = win32_query_perf_counter_time();
|
||||
{
|
||||
PlatformInput input = {};
|
||||
win32_process_messages(mainWindow, &input);
|
||||
PlatformInput platformInput = {};
|
||||
platformInput.deltaForFrame = frameTimeInS;
|
||||
win32_process_messages(mainWindow, &platformInput);
|
||||
|
||||
PlatformRenderBuffer platformBuffer = {};
|
||||
platformBuffer.memory = renderBitmap.memory;
|
||||
platformBuffer.height = renderBitmap.height;
|
||||
platformBuffer.width = renderBitmap.width;
|
||||
dchip8_update(&platformBuffer, &input);
|
||||
dchip8_update(platformBuffer, platformInput, platformMemory);
|
||||
}
|
||||
|
||||
////////////////////////////////////////////////////////////////////////
|
||||
|
|
@ -275,18 +284,18 @@ int WINAPI WinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance,
|
|||
(DWORD)((targetSecondsPerFrame - workTimeInS) * 1000);
|
||||
Sleep(remainingTimeInMs);
|
||||
}
|
||||
|
||||
LARGE_INTEGER endFrameTime = win32_query_perf_counter_time();
|
||||
frameTimeInS =
|
||||
win32_query_perf_counter_get_time(startFrameTime, endFrameTime);
|
||||
f32 msPerFrame = 1000.0f * frameTimeInS;
|
||||
|
||||
wchar_t windowTitleBuffer[128] = {};
|
||||
_snwprintf_s(windowTitleBuffer, ARRAY_COUNT(windowTitleBuffer),
|
||||
ARRAY_COUNT(windowTitleBuffer),
|
||||
L"dchip-8 | %5.2f ms/f", msPerFrame);
|
||||
SetWindowText(mainWindow, windowTitleBuffer);
|
||||
}
|
||||
|
||||
LARGE_INTEGER endFrameTime = win32_query_perf_counter_time();
|
||||
frameTimeInS =
|
||||
win32_query_perf_counter_get_time(startFrameTime, endFrameTime);
|
||||
f32 msPerFrame = 1000.0f * frameTimeInS;
|
||||
|
||||
wchar_t windowTitleBuffer[128] = {};
|
||||
_snwprintf_s(windowTitleBuffer, ARRAY_COUNT(windowTitleBuffer),
|
||||
ARRAY_COUNT(windowTitleBuffer), L"dchip-8 | %5.2f ms/f",
|
||||
msPerFrame);
|
||||
SetWindowText(mainWindow, windowTitleBuffer);
|
||||
}
|
||||
|
||||
return 0;
|
||||
|
|
|
|||
Loading…
Reference in New Issue