137 lines
3.8 KiB
Nim
137 lines
3.8 KiB
Nim
import strformat
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import strutils
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import types/value
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type
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OpCode* = enum
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opReturn, opCall, opCheckArity, opFunctionDef, # functions
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opPop, opPopSA, opPopA # pop
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opPrint, # print
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opNegate, opNot # unary
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opAdd, opSubtract, opMultiply, opDivide, # math
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opEqual, opGreater, opLess, # comparison
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opTrue, opFalse, opNil, # literal
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opConstant, # constant
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opDefineGlobal, opGetGlobal, opSetGlobal, # globals (uses constants)
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opGetLocal, opSetLocal, # locals
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opJumpIfFalse, opJump, opLoop, opJumpIfFalsePop, # jumps
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opCreateList, opCreateTable, # collection creation
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opLen, opSetIndex, opGetIndex, # collection operators
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Chunk* = object
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code*: seq[uint8]
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constants*: seq[NdValue]
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lines*: seq[int]
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name*: string # name of the module/chunk/files
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DoubleUint8* = array[2, uint8]
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# WARNING! short args can safely assumed to be 1 byte long outside of chunk.nim
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const shortArgSize* = 1
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const shortArgMax* = 256 - 1
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# modules outside chunk.nim should not assume any length of argSize, however code inside chunk.nim can make such assumptions
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const argSize* = 2
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const argMax*: int = 256*256 - 1
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proc initChunk*(name: string): Chunk =
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Chunk(code: @[], name: name, lines: @[], constants: @[])
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proc writeChunk*(ch: var Chunk, code: uint8, line: int) =
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ch.code.add(code)
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ch.lines.add(line)
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proc writeChunk*(ch: var Chunk, code: OpCode, line: int) =
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ch.code.add(code.uint8)
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ch.lines.add(line)
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proc writeChunk*(ch: var Chunk, code: DoubleUint8, line: int) =
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for c in code:
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ch.code.add(c)
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ch.lines.add(line)
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proc len*(ch: Chunk): int =
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ch.code.len
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proc toDU8*(integ: int): DoubleUint8 =
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cast[ptr array[2, uint8]](integ.unsafeAddr)[]
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proc toInt*(du8: DoubleUint8): int =
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cast[uint16](du8).int
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proc DU8ptrToInt*(du8: ptr uint8): int =
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cast[ptr uint16](du8)[].int
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proc addConstant*(ch: var Chunk, constant: NdValue): int =
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ch.constants.add(constant)
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ch.constants.high
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proc writeConstant*(ch: var Chunk, constant: NdValue, line: int): int =
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result = ch.addConstant(constant)
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ch.writeChunk(opConstant, line)
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ch.writeChunk(result.toDU8, line)
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const simpleInstructions = {
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opReturn,
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opPop,
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opPrint,
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opNegate, opNot,
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opAdd, opSubtract, opMultiply, opDivide,
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opEqual, opGreater, opLess,
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opTrue, opFalse, opNil,
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opLen, opSetIndex, opGetIndex,
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}
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const constantInstructions = {
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opConstant,
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opDefineGlobal, opGetGlobal, opSetGlobal,
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}
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const shortArgInstructions = {
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opPopSA,
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opCall,
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opCheckArity,
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}
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const argInstructions = {
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opPopA,
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opGetLocal, opSetLocal,
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opJumpIfFalse, opJump, opLoop, opJumpIfFalsePop,
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opFunctionDef,
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opCreateList, opCreateTable,
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}
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proc disassembleChunk*(ch: Chunk) =
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echo &"== Chunk {ch.name} begin =="
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echo "index line instruction"
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var c: int = 0
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var lastLine = -1
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while c < ch.code.len:
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template instruction: uint8 = ch.code[c]
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template line: int = ch.lines[c]
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template double: DoubleUint8 = [ch.code[c+1], ch.code[c+2]]
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template shortArg: uint8 = ch.code[c+1]
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let cFmt = &"{c:04}"
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let lineFmt = if lastLine == line: " | " else: &"{line:04}"
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try:
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write stdout, &"[{cFmt}] {lineFmt} {instruction.OpCode} ({instruction.toHex(2)}"
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case instruction.OpCode:
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of simpleInstructions:
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write stdout, ")\n"
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of shortArgInstructions:
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write stdout, &" {shortArg.toHex(2)}"
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c += 1
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of argInstructions:
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write stdout, &" {double[0].toHex(2)} {double[1].toHex(2)})\n"
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c += 2
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of constantInstructions:
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let i = double.toInt
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write stdout, &" {double[0].toHex(2)} {double[1].toHex(2)})\n"
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echo &" points to constant {ch.constants[i]} (i: {i})"
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c += 2
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except:
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echo &"[{cFmt}] {lineFmt} Unknown opcode {instruction}"
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c.inc
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echo &"== Chunk {ch.name} end =="
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