add: Implement io8 to get and put char

emulator/emulator.go

@@ -5,6 +5,8 @@ type RegisterID int
 const (
 	RegistersCount        = 8
 	MemorySize            = 1024 * 1024
+	AL                    = 0
+	EDX                   = 2
 	ESP                   = 4
 	EBP                   = 5
 	CARRYFLAG      uint32 = 1
@@ -88,6 +90,24 @@ func (reg *Registers) GetRegister32(index byte) uint32 {
 	return 0
 }
 
+func (reg *Registers) getRegister8(index byte) byte {
+	if index < 4 {
+		return byte(reg.GetRegister32(index) & 0xff)
+	} else {
+		return byte((reg.GetRegister32(index-4) >> 8) & 0xff)
+	}
+}
+
+func (reg *Registers) setRegister8(index byte, value byte) {
+	if index < 4 {
+		r := reg.GetRegister32(index) & 0xffffff00
+		reg.setRegister32(index, r|uint32(value))
+	} else {
+		r := reg.GetRegister32(index-4) & 0xffffff00
+		reg.setRegister32(index-4, r|uint32(value)<<8)
+	}
+}
+
 func GetCode8(emu *Emulator, index int) byte {
 	return emu.Memory[int(emu.Eip)+index]
 }

emulator/instruction.go

@@ -249,6 +249,20 @@ func shortJump(emu *Emulator) {
 	emu.Eip += uint32(diff + 2)
 }
 
+func inAlDx(emu *Emulator) {
+	address := emu.Registers.GetRegister32(EDX) & 0xffff
+	value := ioIn8(uint16(address))
+	emu.Registers.setRegister8(AL, value)
+	emu.Eip++
+}
+
+func outDxAl(emu *Emulator) {
+	address := emu.Registers.GetRegister32(EDX) & 0xffff
+	value := emu.Registers.getRegister8(AL)
+	ioOut8(uint16(address), value)
+	emu.Eip++
+}
+
 func Instructions(index byte) (func(emu *Emulator), error) {
 	switch {
 	case 0x01 == index:
@@ -305,6 +319,10 @@ func Instructions(index byte) (func(emu *Emulator), error) {
 		return nearJump, nil
 	case 0xeb == index:
 		return shortJump, nil
+	case 0xec == index:
+		return inAlDx, nil
+	case 0xee == index:
+		return outDxAl, nil
 	case 0xff == index:
 		return codeff, nil
 	}

emulator/io.go

@@ -0,0 +1,25 @@
+package emulator
+
+import (
+	"bufio"
+	"fmt"
+	"os"
+)
+
+func ioIn8(address uint16) uint8 {
+	switch address {
+	case 0x03f8:
+		reader := bufio.NewReader(os.Stdin)
+		input, _ := reader.ReadByte()
+		return input
+	default:
+		return 0
+	}
+}
+
+func ioOut8(address uint16, value uint8) {
+	switch address {
+	case 0x03f8:
+		fmt.Printf("%c", value)
+	}
+}