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assembler - Fix bug where the assembler attempted to handle indirect references to constants twice / Remove unused "assemble with optional args" function / Tidy up debugging printouts

This commit is contained in:
n loewen 2023-08-23 21:23:45 +01:00
parent ee1e899108
commit 78ac43bead
1 changed files with 29 additions and 42 deletions
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71
assembler.js
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@ -74,7 +74,7 @@ function preparseSourceCode(source) {
}
return lines.map((line, index) => {
dbg('2', ` ${line}`);
dbg(1, ` ${line}`);
let info = {
number: index,
source: line,
@ -109,7 +109,7 @@ function decodeNumericOp(arg) {
/**
* @param {string} op
* @param {object} labels // TODO
* @param {object} labels // TODO document better
* @param {number} IP
* @returns {Array<string>} - array of labels
**/
@ -124,10 +124,10 @@ function handleLabelDefinition(op, IP, labels) {
bytesToReplace: [],
};
}
dbg(2, ` Label definition:`);
dbg(2, ` Points to byte: ${labels[label].pointsToByte}`);
dbg(2, ` Bytes to replace: ${labels[label].bytesToReplace}`);
dbg(3, ` IP: $${num2hex(IP)}, new code: none`);
dbg(1, ` Label definition:`);
dbg(1, ` Points to byte: ${labels[label].pointsToByte}`);
dbg(1, ` Bytes to replace: ${labels[label].bytesToReplace}`);
dbg(1, ` IP: $${num2hex(IP)}, new code: none`);
dbgGroupEnd(1, 'Input line');
return labels;
}
@ -151,21 +151,6 @@ function handleConstantDefinitions(op, arg, IP, constants) {
return constants;
}
/**
* @param {SourceLineInfo} line
* @returns {Object}
**/
function assembleMnemonicsWithOptionalArgs(line) {
if (mnemonicsWithOptionalArgs.indexOf(line.operation) < 0) {
console.error(`Missing opcode for line ${line.number}: ${line.source}`);
throw new Error("Missing opcode");
}
let opcode = decodeNumericOp(line.operation);
console.log('decoding op without operand', line);
let operand = line.argument !== null ? decodeNumericOp(line.argument) : 0;
return [opcode, operand];
}
/**
* Assemble source code.
@ -177,12 +162,12 @@ function assembleMnemonicsWithOptionalArgs(line) {
* @return TODO
**/
function decodeInstructions(source) {
dbg(2, 'Pre-parsing...');
dbg(1, 'Pre-parsing...');
let lines = preparseSourceCode(source);
dbg(2, '');
dbg(2, 'Done pre-parsing.');
dbg(2, '');
dbg(2, 'Assembling...');
dbg(1, '');
dbg(1, 'Done pre-parsing.');
dbg(1, '');
dbg(1, 'Assembling...');
// Figure out where to start assembly...
@ -280,34 +265,35 @@ function decodeInstructions(source) {
bytesToReplace: [IP + 1],
};
}
dbg(2, ` Label reference:`);
dbg(2, ` Points to byte: ${labels[label].pointsToByte}`);
dbg(2, ` Bytes to replace: ${labels[label].bytesToReplace}`);
dbg(1, `Label reference:`);
dbg(1, ` Points to byte: ${labels[label].pointsToByte}`);
dbg(1, ` Bytes to replace: ${labels[label].bytesToReplace}`);
decodedArg = 0; // Return 0 for operand for now -- we'll replace it later
}
// Operands - Handle references to the Instruction Pointer
if (arg !== null && arg === ASM_IP_LABEL) {
dbg(2, ` References current IP - ${IP}`);
dbg(1, ` References current IP - ${IP}`);
decodedArg = IP;
}
// Operands - Handle references to constants
if (arg !== null && arg.startsWith(ASM_CONSTANT_PREFIX)) {
dbg(2, ` References '${arg}'`);
decodedArg = constants[arg.substring(1)]; // substring(1) strips '>'
dbg(1, `References '${arg}'`);
decodedArg = decodeNumericOp(constants[arg.substring(1)]); // substring(1) strips '>'
}
// Operands - Handle references to constants in indirect mode
if (arg !== null && arg.startsWith(`(${ASM_CONSTANT_PREFIX}`)) {
addressingMode = "indirect";
dbg(2, ` (Indirectly) References '${arg}'`);
let constTemp = arg.replace(`(${ASM_CONSTANT_PREFIX}`, "").replace(")", "");
decodedArg = constants[constTemp];
dbg(1, `(Indirectly) References '${arg}'`);
let constName = arg.replace(`(${ASM_CONSTANT_PREFIX}`, "");
constName = constName.replace(")", "");
decodedArg = decodeNumericOp(constants[constName]);
}
// Operands - Handle indirect expressions
if (arg !== null && arg.startsWith("(")) {
if (arg !== null && decodedArg === null && arg.startsWith("(")) {
addressingMode = "indirect";
let indyTemp = arg.replace("(", "").replace(")", "");
decodedArg = decodeNumericOp(indyTemp);
@ -318,11 +304,13 @@ function decodeInstructions(source) {
decodedOp = mnemonics2opcodes[line.operation][addressingMode];
}
// Decode regular operands
if (decodedArg === null) {
decodedArg = decodeNumericOp(line.argument);
}
machineCode[IP] = decodedOp;
machineCode[IP + 1] = decodedArg;
@ -336,7 +324,6 @@ function decodeInstructions(source) {
dbg(3, ` Machine code: $${num2hex(decodedOp)} $${num2hex(decodedArg)}`);
dbg(3, ` IP: $${num2hex(IP)}`);
dbg(3, '');
IP += 2;
};
}
@ -347,11 +334,11 @@ function decodeInstructions(source) {
// Backfill label references
for (let k of Object.keys(labels)) {
dbgGroup(2, `${ASM_LABEL_PREFIX}${k}`);
dbgGroup(1, `${ASM_LABEL_PREFIX}${k}`);
let label = labels[k];
dbg(2, `Points to byte: ${label.pointsToByte}`);
dbg(2, `Bytes to replace: ${label.bytesToReplace}`);
dbgGroupEnd(2, `label`);
dbg(1, `Points to byte: ${label.pointsToByte}`);
dbg(1, `Bytes to replace: ${label.bytesToReplace}`);
dbgGroupEnd(1);
for (let j = 0; j < label.bytesToReplace.length; j++) {
machineCode[label.bytesToReplace[j]] = label.pointsToByte;
}