67 lines
1.3 KiB
Go
67 lines
1.3 KiB
Go
package compiler
|
|
|
|
import (
|
|
"fmt"
|
|
)
|
|
|
|
// MakeInstruction returns a bytecode for an opcode and the operands.
|
|
func MakeInstruction(opcode Opcode, operands ...int) []byte {
|
|
def, ok := Lookup(opcode)
|
|
if !ok {
|
|
return nil
|
|
}
|
|
|
|
totalLen := 1
|
|
for _, w := range def.Operands {
|
|
totalLen += w
|
|
}
|
|
|
|
instruction := make([]byte, totalLen, totalLen)
|
|
instruction[0] = byte(opcode)
|
|
|
|
offset := 1
|
|
for i, o := range operands {
|
|
width := def.Operands[i]
|
|
switch width {
|
|
case 1:
|
|
instruction[offset] = byte(o)
|
|
case 2:
|
|
n := uint16(o)
|
|
instruction[offset] = byte(n >> 8)
|
|
instruction[offset+1] = byte(n)
|
|
}
|
|
offset += width
|
|
}
|
|
|
|
return instruction
|
|
}
|
|
|
|
// FormatInstructions returns string representation of
|
|
// bytecode instructions.
|
|
func FormatInstructions(b []byte, posOffset int) []string {
|
|
var out []string
|
|
|
|
i := 0
|
|
for i < len(b) {
|
|
def, ok := Lookup(Opcode(b[i]))
|
|
if !ok {
|
|
out = append(out, fmt.Sprintf("error: unknown Opcode %d", b[i]))
|
|
continue
|
|
}
|
|
|
|
operands, read := ReadOperands(def, b[i+1:])
|
|
|
|
switch len(def.Operands) {
|
|
case 0:
|
|
out = append(out, fmt.Sprintf("%04d %-7s", posOffset+i, def.Name))
|
|
case 1:
|
|
out = append(out, fmt.Sprintf("%04d %-7s %-5d", posOffset+i, def.Name, operands[0]))
|
|
case 2:
|
|
out = append(out, fmt.Sprintf("%04d %-7s %-5d %-5d", posOffset+i, def.Name, operands[0], operands[1]))
|
|
}
|
|
|
|
i += 1 + read
|
|
}
|
|
|
|
return out
|
|
}
|