diff options
Diffstat (limited to 'vendor/github.com/d5/tengo/v2/instructions.go')
-rw-r--r-- | vendor/github.com/d5/tengo/v2/instructions.go | 61 |
1 files changed, 61 insertions, 0 deletions
diff --git a/vendor/github.com/d5/tengo/v2/instructions.go b/vendor/github.com/d5/tengo/v2/instructions.go new file mode 100644 index 00000000..eb1fbf27 --- /dev/null +++ b/vendor/github.com/d5/tengo/v2/instructions.go @@ -0,0 +1,61 @@ +package tengo + +import ( + "fmt" + + "github.com/d5/tengo/v2/parser" +) + +// MakeInstruction returns a bytecode for an opcode and the operands. +func MakeInstruction(opcode parser.Opcode, operands ...int) []byte { + numOperands := parser.OpcodeOperands[opcode] + + totalLen := 1 + for _, w := range numOperands { + totalLen += w + } + + instruction := make([]byte, totalLen) + instruction[0] = opcode + + offset := 1 + for i, o := range operands { + width := numOperands[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) { + numOperands := parser.OpcodeOperands[b[i]] + operands, read := parser.ReadOperands(numOperands, b[i+1:]) + + switch len(numOperands) { + case 0: + out = append(out, fmt.Sprintf("%04d %-7s", + posOffset+i, parser.OpcodeNames[b[i]])) + case 1: + out = append(out, fmt.Sprintf("%04d %-7s %-5d", + posOffset+i, parser.OpcodeNames[b[i]], operands[0])) + case 2: + out = append(out, fmt.Sprintf("%04d %-7s %-5d %-5d", + posOffset+i, parser.OpcodeNames[b[i]], + operands[0], operands[1])) + } + i += 1 + read + } + return out +} |