mirror of
https://github.com/arnaucube/go-chip8.git
synced 2026-02-06 19:16:46 +01:00
Add Sdl, Add opcodes & descriptions
This commit is contained in:
arnaucube
269
main.go
269
main.go
@@ -4,8 +4,14 @@ import (
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"flag"
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"fmt"
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"io/ioutil"
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"math/rand"
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"github.com/veandco/go-sdl2/sdl"
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)
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const w = 64
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const h = 32
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type chip8 struct {
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opcode uint16
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memory [4096]byte
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@@ -16,7 +22,7 @@ type chip8 struct {
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index uint16
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pc uint16
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gfx [64 * 32]byte
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gfx [w * h]byte
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delayTimer byte
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soundTimer byte
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@@ -27,6 +33,9 @@ type chip8 struct {
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key [16]byte
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drawFlag bool
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// graphics
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renderer *sdl.Renderer
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}
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// Initialize registers and memory once
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@@ -40,6 +49,11 @@ func (c *chip8) initialize() {
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func (c *chip8) emulateCycle() {
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// Fetch Opcode
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c.opcode = uint16(c.memory[c.pc])<<8 | uint16(c.memory[c.pc+1])
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x := byte((c.opcode & 0x0F00) >> 8)
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y := byte((c.opcode & 0x00F0) >> 4)
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nn := byte(c.opcode & 0x00FF)
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nnn := uint16(c.opcode & 0x0FFF)
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fmt.Printf("%X\n", c.opcode)
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// Decode Opcode
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// https://en.wikipedia.org/wiki/CHIP-8#Opcode_table
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@@ -47,34 +61,92 @@ func (c *chip8) emulateCycle() {
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switch c.opcode & 0xF000 {
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case 0x0000:
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switch c.opcode & 0x000F {
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case 0x0000: // 0x00E0
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// clear screen
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// TODO
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case 0x0000:
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// 00E0 Clear screen
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for i := 0; i < len(c.gfx); i++ {
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c.gfx[i] = 0
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}
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c.pc += 2
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c.drawFlag = true
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break
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case 0x000E: // 0x00EE
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// TODO
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case 0x000E:
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// 00EE Returns from a subroutine
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c.sp--
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c.pc = c.stack[c.sp]
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break
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default:
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fmt.Printf("Unknown opcode [0x0000]: 0x%X\n", c.opcode)
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}
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case 0x1000:
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// 1NNN Jumps to address NNN
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// c.pc = c.opcode & 0x0FFF
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c.pc = nnn
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break
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case 0x2000:
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// 2NNN Calls subroutine at NNN
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c.stack[c.sp] = c.pc
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c.sp++
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c.pc = c.opcode & 0x0FFF
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// c.pc = c.opcode & 0x0FFF
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c.pc = nnn
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break
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case 0x3000:
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// 3XNN Skips the next instruction if VX equals NN. (Usually
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// the next instruction is a jump to skip a code block)
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fmt.Println(c.v[x], nn)
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if c.v[x] == nn {
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c.pc += 2
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}
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c.pc += 2
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break
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case 0x4000:
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// 4XNN Skips the next instruction if VX doesn't equal NN.
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// (Usually the next instruction is a jump to skip a code
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// block)
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if c.v[x] != nn {
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c.pc += 2
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}
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c.pc += 2
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break
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case 0x5000:
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// 5XY0 Skips the next instruction if VX equals VY. (Usually
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// the next instruction is a jump to skip a code block)
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if c.v[x] != c.v[y] {
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c.pc += 2
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}
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c.pc += 2
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break
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case 0x6000:
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pos := (c.opcode & 0x0F00) >> 8
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c.v[pos] = byte(c.opcode)
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// 6XNN Sets VX to NN
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c.v[x] = nn
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c.pc += 2
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break
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case 0x7000:
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c.v[c.opcode&0x0F00>>8] += byte(c.opcode)
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// 7XNN Adds NN to VX. (Carry flag is not changed)
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// c.v[c.opcode&0x0F00>>8] += byte(c.opcode)
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c.v[x] += nn
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c.pc += 2
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break
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case 0x8000:
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switch c.opcode & 0x000F {
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case 0x0004: // 0x8XY4
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case 0x0000:
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// 0x8XY0 Sets VX to the value of VY
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c.v[x] = c.v[y]
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c.pc += 2
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case 0x0001:
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// 0x8XY1 Sets VX to VX or VY. (Bitwise OR operation)
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c.v[x] = (c.v[x] | c.v[y])
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c.pc += 2
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case 0x0002:
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// 0x8XY2 Sets VX to VX and VY. (Bitwise AND operation)
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c.v[x] = (c.v[x] & c.v[y])
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c.pc += 2
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case 0x0003:
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// 0x8XY3 Sets VX to VX xor VY
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c.v[x] = (c.v[x] ^ c.v[y])
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c.pc += 2
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case 0x0004:
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// 0x8XY4 Adds VY to VX. VF is set to 1 when there's a
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// carry, and to 0 when there isn't
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if c.v[(c.opcode&0x00F0)>>4] > (0xFF - c.v[c.opcode&0x0F00]) {
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c.v[0xF] = 1
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} else {
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@@ -83,17 +155,80 @@ func (c *chip8) emulateCycle() {
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c.v[(c.opcode&0x0F00)>>8] += c.v[(c.opcode&0x00F0)>>4]
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c.pc += 2
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break
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case 0x0005:
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// 0x8XY5 VY is subtracted from VX. VF is set to 0 when
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// there's a borrow, and 1 when there isn't
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if c.v[x] > c.v[y] {
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c.v[0xF] = 0x1
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} else {
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c.v[0xF] = 0x0
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}
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c.v[x] -= c.v[y]
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c.pc += 2
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case 0x0006:
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// 0x8XY6 Stores the least significant bit of VX in VF
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// and then shifts VX to the right by 1
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if c.opcode&0x1 >= 1 {
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c.v[0xF] = 1
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} else {
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c.v[0xF] = 0
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}
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c.v[x] = c.v[x] >> 1
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c.pc += 2
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case 0x0007:
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// 0x8XY7 Sets VX to VY minus VX. VF is set to 0 when
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// there's a borrow, and 1 when there isn't
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if c.v[y] > c.v[x] {
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c.v[0xF] = 0x1
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} else {
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c.v[0xF] = 0x0
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}
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c.v[x] = c.v[y] - c.v[x]
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c.pc += 2
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case 0x000E:
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// 0x8XYE Stores the most significant bit of VX in VF
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// and then shifts VX to the left by 1
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if c.opcode&0x80 == 0x80 {
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c.v[0xF] = 1
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} else {
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c.v[0xF] = 0
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}
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c.v[x] = c.v[x] << 1
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c.pc += 2
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default:
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fmt.Printf("Unknown opcode [0x8000]: 0x%X\n", c.opcode)
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}
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case 0x9000:
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// 9XY0 Skips the next instruction if VX doesn't equal VY.
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// (Usually the next instruction is a jump to skip a code
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// block)
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if c.v[x] != c.v[y] {
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c.pc += 2
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}
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c.pc += 2
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case 0xA000:
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// set index to NNN position
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// ANNN set index to NNN position
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c.index = c.opcode & 0x0FFF
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c.pc += 2
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break
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case 0xB000:
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// BNNN Jumps to the address NNN plus V0
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c.pc = nnn + uint16(c.v[0])
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case 0xC000:
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// CXNN Sets VX to the result of a bitwise and operation on a
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// random number (Typically: 0 to 255) and NN
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r := byte(rand.Intn(255))
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c.v[x] = r & nn
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c.pc += 2
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case 0xD000:
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x := uint16(c.v[(c.opcode&0x0F00)>>8])
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y := uint16(c.v[(c.opcode&0x00F0)>>4])
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// DXYN Draws a sprite at coordinate (VX, VY) that has a width
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// of 8 pixels and a height of N+1 pixels. Each row of 8 pixels
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// is read as bit-coded starting from memory location I; I
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// value doesn’t change after the execution of this
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// instruction. As described above, VF is set to 1 if any
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// screen pixels are flipped from set to unset when the sprite
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// is drawn, and to 0 if that doesn’t happen
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fmt.Printf("D: %X\n", c.opcode)
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height := c.opcode & 0x000F
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var pixel byte
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@@ -102,35 +237,75 @@ func (c *chip8) emulateCycle() {
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pixel = c.memory[c.index+yline]
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for xline := uint16(0); xline < 8; xline++ {
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if (pixel & (0x80 >> xline)) != 0 {
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if c.gfx[(x+xline+((y+yline)*64))] == 1 {
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if c.gfx[(w*(uint16(y)+yline)+(uint16(x)+xline))] == 1 {
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c.v[0xF] = 1
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}
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c.gfx[x+xline+((y+yline)*64)] ^= 1
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c.gfx[w*(uint16(y)+yline)+(uint16(x)+xline)] ^= 1
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}
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}
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}
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// for yline := uint16(0); yline < height; yline++ {
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// pixel = c.memory[c.index+yline]
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// for xline := uint16(0); xline < 8; xline++ {
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// if (pixel & (0x80 >> xline)) != 0 {
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// if c.gfx[(uint16(x)+xline+((uint16(y)+yline)*64))] == 1 {
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// c.v[0xF] = 1
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// }
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// c.gfx[uint16(x)+xline+((uint16(y)+yline)*64)] ^= 1
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// }
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// }
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//
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// }
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c.drawFlag = true
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c.pc += 2
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break
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case 0xE000:
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switch c.opcode & 0x00FF {
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case 0x009E:
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// EX9E Skips the next instruction if the key stored in
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// VX is pressed. (Usually the next instruction is a
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// jump to skip a code block)
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if c.key[c.v[(c.opcode&0x0F00)>>8]] != 0 {
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c.pc += 4
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} else {
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c.pc += 2
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}
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break
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case 0x00A1:
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// EXA1 Skips the next instruction if the key stored in
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// VX isn't pressed. (Usually the next instruction is a
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// jump to skip a code block)
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// TODO
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c.pc += 2
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}
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break
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case 0xF000:
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x := (c.opcode & 0x0F00) >> 8
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fmt.Printf("F: 0x%X\n", c.opcode)
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switch c.opcode & 0x00FF {
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case 0x0029:
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case 0x0007:
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// FX07 Sets VX to the value of the delay timer
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c.v[x] = c.delayTimer
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c.pc += 2
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case 0x000A:
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// FX0A A key press is awaited, and then stored in VX.
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// (Blocking Operation. All instruction halted until
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// next key event)
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// TODO
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// c.index = uint16(c.v[x]) *
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c.pc += 2
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case 0x0015:
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// FX15 Sets the delay timer to VX
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c.delayTimer = c.v[x]
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c.pc += 2
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case 0x0018:
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// FX18 Sets the sound timer to VX
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c.soundTimer = c.v[x]
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c.pc += 2
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case 0x001E:
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// FX1E Adds VX to I. VF is not affected
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c.index += uint16(c.v[x])
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c.pc += 2
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case 0x0029:
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// FX29 Sets I to the location of the sprite for the character in VX. Characters 0-F (in hexadecimal) are represented by a 4x5 font
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c.index = uint16(c.v[x]) * 5
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c.pc += 2
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break
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case 0x0033:
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@@ -139,8 +314,21 @@ func (c *chip8) emulateCycle() {
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c.memory[c.index+2] = (c.v[x] / 100) % 10
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c.pc += 2
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break
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case 0x0055:
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// FX55 Stores V0 to VX (including VX) in memory
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// starting at address I. The offset from I is
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// increased by 1 for each value written, but I itself
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// is left unmodified
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for i := uint16(0); i <= uint16(x); i++ {
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c.memory[c.index+i] = c.v[i]
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}
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c.pc += 2
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case 0x0065:
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for i := uint16(0); i < x+1; i++ {
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// 0xFX65 Fills V0 to VX (including VX) with values
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// from memory starting at address I. The offset from I
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// is increased by 1 for each value written, but I
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// itself is left unmodified
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for i := uint16(0); i < uint16(x)+1; i++ {
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c.v[i] = c.memory[c.index+i]
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}
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c.pc += 2
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@@ -195,8 +383,37 @@ var fontSet = [80]byte{
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0xF0, 0x80, 0xF0, 0x80, 0x80, // F
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}
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func (c *chip8) drawGraphics() {
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func (c *chip8) setupInput() {
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}
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func (c *chip8) setupGraphics() {
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window, err := sdl.CreateWindow("go-chip8", sdl.WINDOWPOS_UNDEFINED,
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sdl.WINDOWPOS_UNDEFINED, w, h, sdl.WINDOW_SHOWN)
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if err != nil {
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panic(err)
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}
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c.renderer, err = sdl.CreateRenderer(window, -1, 0)
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if err != nil {
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panic(err)
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}
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}
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func (c *chip8) drawGraphics() {
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c.renderer.SetDrawColor(255, 255, 255, 1)
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x := 0
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y := 0
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for i := 0; i < len(c.gfx); i++ {
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if i%w == 0 {
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// jump line
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x = 0
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y++
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}
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if c.gfx[i]^1 == 1 {
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c.renderer.DrawPoint(int32(x), int32(y))
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}
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}
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c.renderer.Present()
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c.drawFlag = false
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}
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func (c *chip8) setKeys() {
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@@ -208,10 +425,10 @@ func main() {
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flag.Parse()
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// setupGraphics()
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// setupInput()
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var c chip8
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c.setupGraphics()
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c.setupInput()
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c.initialize()
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err := c.loadGame(*filepath)
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if err != nil {
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Reference in New Issue
Block a user