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Restructure overall assembler. Add string_util and Docs

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sBubshait 2024-06-15 01:50:56 +01:00
parent 3501ac93aa
commit 6de1915dbe
11 changed files with 587 additions and 333 deletions
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2
src/Makefile
View File

@ -9,7 +9,7 @@ CFLAGS ?= -std=c17 -g\
all: assemble
assemble: assemble.o parser.o fileio.o
assemble: assemble.o parser.o fileio.o tokeniser.o string_util.o
emulate: emulate.o
clean:

12
src/assemble.c
View File

@ -1,3 +1,9 @@
/** @file assemble.c
* @brief The main file for the ARMv8 assembler. Reads an assembly file and outputs the binary file.
*
* @author Saleh Bubshait
*/
#include <stdlib.h>
#include <stdio.h>
#include "a64instruction/a64instruction.h"
@ -31,11 +37,13 @@ int main(int argc, char **argv) {
// Write the binary to the output file
writeBinaryFile(binary, argv[2], lineCount);
/* TODO: FREE MEMORY!! */
return EXIT_SUCCESS;
}
/** The first pass of the assembler. Creates the symbol table. Adds all labels
* and the address of the instruction following the label to the symbol table.
* Returns the final symbol table.
*/
static symbol_table *firstPass(a64inst_instruction *instructions, int lineCount) {
symbol_table *table = st_init();
int labelCount = 0;

21
src/encode.c
View File

@ -1,3 +1,12 @@
/** @file encode.c
* @brief A function to encode the internal representation of ARMv8
* instructions, a64inst_instruction, into binary.
*
* @author Ethan Dias Alberto
* @author George Niedringhaus
* @author Saleh Bubshait
*/
#include <assert.h>
#include "global.h"
#include "a64instruction/a64instruction.h"
@ -53,7 +62,7 @@ static int getLabelOffset(symbol_table* table, char* label, int currentIndex, in
}
// Generates assembled code based on the two-pass assembly method
word encodeBranch(a64inst_instruction *instr, int index, symbol_table *st) {
static word encodeBranch(a64inst_instruction *instr, int index, symbol_table *st) {
word wrd = 0;
switch (instr->data.BranchData.BranchType) {
@ -77,7 +86,7 @@ word encodeBranch(a64inst_instruction *instr, int index, symbol_table *st) {
return wrd;
}
word encodeDPImmediate(a64inst_instruction inst) {
static word encodeDPImmediate(a64inst_instruction inst) {
word wrd = 0;
a64inst_DPImmediateData data = inst.data.DPImmediateData;
@ -104,7 +113,7 @@ word encodeDPImmediate(a64inst_instruction inst) {
return wrd;
}
word encodeDPRegister(a64inst_instruction inst) {
static word encodeDPRegister(a64inst_instruction inst) {
word wrd = 0;
a64inst_DPRegisterData data = inst.data.DPRegisterData;
@ -139,7 +148,7 @@ word encodeDPRegister(a64inst_instruction inst) {
}
word encodeSingleDataTransfer(a64inst_instruction inst) {
static word encodeSingleDataTransfer(a64inst_instruction inst) {
word wrd = 0;
a64inst_SingleTransferData data = inst.data.SingleTransferData;
@ -175,7 +184,7 @@ word encodeSingleDataTransfer(a64inst_instruction inst) {
return wrd;
}
word encodeLoadLiteral(a64inst_instruction cI, int arrIndex, symbol_table *st) {
static word encodeLoadLiteral(a64inst_instruction cI, int arrIndex, symbol_table *st) {
word wrd = 0;
a64inst_SingleTransferData data = cI.data.SingleTransferData;
@ -189,7 +198,7 @@ word encodeLoadLiteral(a64inst_instruction cI, int arrIndex, symbol_table *st) {
return wrd;
}
word *encode(a64inst_instruction insts[], int instCount, symbol_table* st) {
static word *encode(a64inst_instruction insts[], int instCount, symbol_table* st) {
word *arr = (word*)malloc(sizeof(word) * instCount);
int index = 0;
for (int i = 0; i < instCount; i++) {

443
src/parser.c
View File

@ -1,24 +1,50 @@
/** @file parser.c
* @brief Functions to parse ARMv8 assembly lines into an array of a special
* internal representation of instructions, a64inst_instruction.
* @author Ethan Dias Alberto
* @author George Niedringhaus
* @author Saleh Bubshait
*/
#include <assert.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <ctype.h>
#include <stdbool.h>
#include "parser.h"
#include "a64instruction/a64instruction.h"
#include "global.h"
#include "tokeniser.c"
#include "tokeniser.h"
#include "string_util.h"
/** Prototypes */
void parse_instruction(char asmLine[], a64inst_instruction *instr);
static char *duplicateString(char *str);
void parseSingleTransfer(a64inst_instruction *instr, char *opcode, char *operandList[], int numOperands);
void parseBranch(a64inst_instruction *instr, char* opcode, char *operandList[]);
void calculateAddressFormat(a64inst_instruction *instr, char *operandList[], int numOperands);
void parseDPImmediate(a64inst_instruction *inst, char *tokens[], int tokensCount);
void parseDPRegister(a64inst_instruction *inst, char *tokens[], int tokensCount);
void parseDirective(a64inst_instruction *inst, char *tokens[]);
/************************************
* STRUCTS
************************************/
typedef struct {
int type;
int immediate;
} ShiftData;
/************************************
* PROTOTYPES
************************************/
static void parse_instruction(char asmLine[], a64inst_instruction *instr);
static void parseSingleTransfer(a64inst_instruction *instr, char *opcode, char *operandList[], int numOperands);
static void parseBranch(a64inst_instruction *instr, char* opcode, char *operandList[]);
static void parseAddressingMode(a64inst_instruction *instr, char *operandList[], int numOperands);
static void parseDPImmediate(a64inst_instruction *inst, char *tokens[], int tokensCount);
static void parseDPRegister(a64inst_instruction *inst, char *tokens[], int tokensCount);
static void parseDirective(a64inst_instruction *inst, char *tokens[]);
static ShiftData *parseShift(char *shift);
static void classifyOpcode(char* opcode, a64inst_instruction *instr, char *tokens[], int *tokensCount);
/************************************
* CONSTANTS
************************************/
/** Constants */
static const char *BRANCH_OPCODES[] = {"b", "br", "b.eq", "b.ne", "b.ge", "b.lt", "b.gt", "b.le", "b.al"};
static const char *SINGLE_TRANSFER_OPCODES[] = {"ldr", "str"};
static const char *WIDE_MOV_OPCODES[] = {"movn", "movz", "movz", "movk"};
@ -26,9 +52,11 @@ static const char *ARITHMETIC_OPCODES[] = {"add", "adds", "sub", "subs"};
static const char *MULTIPLY_OPCODES[] = {"mul", "madd", "msub", "mneg"};
static const char *SHIFT_TYPE_OPCODES[] = {"lsl", "lsr", "asr", "ror"};
static const char *LOGIC_OPCODES[] = {"and", "ands", "bic", "bics", "eor", "eon", "orr", "orn"};
static const char *ZERO_REGISTER_ALIAS[] = {"xzr", "wzr"};
static const char *ALIAS_OPCODES[] = {"cmp", "cmn", "neg", "negs", "tst", "mvn", "mov"};
static char *ALIAS_TARGET_OPCODES[] = {"subs", "adds", "sub", "subs", "ands", "orn", "orr"};
/************************************
* FUNCTIONS
************************************/
a64inst_instruction *parse(char **asmLines, int lineCount) {
a64inst_instruction *instructions = malloc(sizeof(a64inst_instruction) * lineCount);
@ -42,176 +70,29 @@ a64inst_instruction *parse(char **asmLines, int lineCount) {
return instructions;
}
static char *duplicateString(char *str) {
char *newStr = malloc(strlen(str) + 1);
strcpy(newStr, str);
return newStr;
}
static bool isStringIn(char *str, const char *arr[], int arrSize) {
for (int i = 0; i < arrSize; i++) {
if (strcmp(str, arr[i]) == 0) {
return true;
}
}
return false;
}
// If more than one occurance, return the last index
static int indexStringIn(char *str, const char *arr[], int arrSize) {
for (int i = arrSize - 1; i >= 0; i--) {
if (strcmp(str, arr[i]) == 0) {
return i;
}
}
return -1;
}
typedef struct {
int type;
int immediate;
} ShiftData;
static ShiftData *parseShift(char *shift) {
char buffer[100];
strcpy(buffer, shift);
char *shiftType = strtok(buffer, " ");
char *shiftAmount = strtok(NULL, " ");
ShiftData *data = malloc(sizeof(ShiftData));
data->type = indexStringIn(shiftType, SHIFT_TYPE_OPCODES, 4);
while (*shiftAmount == ' ' || *shiftAmount == '#') {
shiftAmount++;
}
data->immediate = atoi(shiftAmount);
return data;
}
int isOperandRegister(char regStartChar) {
return((regStartChar == 'x') || (regStartChar == 'w'));
}
int classifyDPInst(char *operandList[]){
return(isOperandRegister(operandList[1][0]) &&
isOperandRegister(operandList[2][0]) &&
isOperandRegister(operandList[3][0]));
}
void classifyAlias(char *opcode, a64inst_instruction *instr, char *tokens[], int *tokensCount) {
int aliasIndex = indexStringIn(opcode, ALIAS_OPCODES, 9);
if (aliasIndex != -1) {
// The instruction is one of the aliases, convert into the target.
char *opcode = ALIAS_TARGET_OPCODES[aliasIndex];
// To correctly encode the zero register, which is either w31 or x31.
char *start_zeroReg = tokens[1];
while (isspace(*start_zeroReg)) start_zeroReg++;
char *zeroReg = malloc(5 * sizeof(char));
*zeroReg = *start_zeroReg;
strcat(zeroReg, "31");
switch(aliasIndex) {
case 0: // cmp -> subs rzr, rn, <op2>
case 1: // cmn -> adds rzr, rn, <op2>
case 4: // tst -> ands rzr, rn, <op2>
// Convert from [instr] REG, <op2> to [instr] RZR, REG, <op2>
tokens[0] = opcode;
tokens[4] = tokens[3];
tokens[3] = tokens[2];
tokens[2] = tokens[1];
tokens[1] = zeroReg;
(*tokensCount)++;
break;
case 2: // neg -> subs rd, rzr, <op2>
case 3: // negs -> subs rd, rzr, <op2>
case 5: // mvn -> orn rd, rzr, <op2>
case 6: // mov -> orr rd, rzr, rm
tokens[0] = opcode;
tokens[4] = tokens[3];
tokens[3] = tokens[2];
tokens[2] = zeroReg;
(*tokensCount)++;
break;
default:
break;
}
}
}
void classifyOpcode(char* opcode, a64inst_instruction *instr, char *tokens[], int *tokensCount){
classifyAlias(opcode, instr, tokens, tokensCount);
if (isStringIn(opcode, BRANCH_OPCODES, 9)) {
instr->type = a64inst_BRANCH;
if (strcmp(opcode, "br") == 0) {
instr->data.BranchData.BranchType = a64inst_REGISTER;
} else if (strcmp(opcode, "b") == 0) {
instr->data.BranchData.BranchType = a64inst_UNCONDITIONAL;
} else {
instr->data.BranchData.BranchType = a64inst_CONDITIONAL;
}
} else if (isStringIn(opcode, SINGLE_TRANSFER_OPCODES, 2)) {
instr->type = a64inst_SINGLETRANSFER;
if (*tokens[2] == '[') {
instr->data.SingleTransferData.SingleTransferOpType = a64inst_SINGLE_TRANSFER_SINGLE_DATA_TRANSFER;
instr->data.SingleTransferData.processOpData.singleDataTransferData.transferType = strcmp(opcode, "ldr") == 0;
} else {
instr->type = a64inst_LOADLITERAL;
}
} else if (classifyDPInst(tokens)) {
instr->type = a64inst_DPREGISTER;
} else {
instr->type = a64inst_DPIMMEDIATE;
}
}
//takes inputted char array and returns the integer of the operand, skipping the first character
//e.g. for a passed "R32", it skips the 'R' and returns 32
int getOperandNumber(char *operand){
if (isStringIn(operand, ZERO_REGISTER_ALIAS, 2)) {
return ZERO_REGISTER;
}
char operandCpy[strlen(operand)];
strcpy(operandCpy, operand+1);
char **endptr = NULL;
int number;
if(strncmp(operandCpy, "0x", 2)==0){
//hex value
strcpy(operandCpy, operand+3);
number = strtol(operandCpy, endptr, 16);
} else if(operandCpy[0] == 'x'){
number = strtol(operandCpy+1, endptr, 16);
} else {
number = strtol(operandCpy, endptr, 10);
}
return number;
}
void parse_instruction(char asmLine[], a64inst_instruction *instr) {
/** Parses a single ARMv8 assembly line into an a64inst_instruction.
*/
static void parse_instruction(char asmLine[], a64inst_instruction *instr) {
if (instr == NULL){
exit(EXIT_FAILURE);
}
if(strcmp(asmLine, HALT_ASM_CMD) == 0){
instr->type = a64inst_HALT;
return;
}
char *asmLineCopy = duplicateString(asmLine);
int tokensCount = 0;
char **tokens = tokenise(asmLineCopy, &tokensCount);
char *opcode = tokens[0];
// Check if the instruction is the halt instruction, "and x0, x0, x0".
if (tokensCount == 4 && strcmp(opcode, "and") == 0
&& getRegister(tokens[1]) == 0
&& getRegister(tokens[2]) == 0
&& getRegister(tokens[3]) == 0) {
instr->type = a64inst_HALT;
return;
}
if(strcmp(opcode, ".int") == 0){
// Directive
instr->type = a64inst_DIRECTIVE;
@ -226,6 +107,8 @@ void parse_instruction(char asmLine[], a64inst_instruction *instr) {
} else {
// Instruction
// Classify the opcode into the correct instruction type.
classifyOpcode(opcode, instr, tokens, &tokensCount);
switch(instr->type){
@ -235,74 +118,32 @@ void parse_instruction(char asmLine[], a64inst_instruction *instr) {
case a64inst_SINGLETRANSFER:
parseSingleTransfer(instr, opcode, tokens, tokensCount);
calculateAddressFormat(instr, tokens, tokensCount);
parseAddressingMode(instr, tokens, tokensCount);
break;
case a64inst_LOADLITERAL:
parseSingleTransfer(instr, opcode, tokens, tokensCount);
break;
case a64inst_DPREGISTER:
//generate DP operands;
parseDPRegister(instr, tokens, tokensCount);
break;
case a64inst_DPIMMEDIATE:
parseDPImmediate(instr, tokens, tokensCount);
break;
default:
printf("Error: Invalid Instruction\n");
printf("Error: Invalid Instruction, '%s'\n", opcode);
break;
}
}
/* TODO: FREE MEMORY! */
}
void calculateAddressFormat(a64inst_instruction *instr, char *tokens[], int tokenCount) {
assert(*tokens[2] == '[');
int operandCount = 0;
char unsplitString[strlen(tokens[2])];
strcpy(unsplitString, tokens[2]);
char **operands = tokeniseOperands(tokens[2], &operandCount);
int baseRegister = getOperandNumber(operands[0]);
instr->data.SingleTransferData.processOpData.singleDataTransferData.base = baseRegister;
if (tokenCount >= 4) {
instr->data.SingleTransferData.processOpData.singleDataTransferData.addressingMode = a64inst_POST_INDEXED;
instr->data.SingleTransferData.processOpData.singleDataTransferData.a64inst_addressingModeData.indexedOffset = getOperandNumber(tokens[3]);
} else if(unsplitString[strlen(unsplitString)-1] == '!') {
instr->data.SingleTransferData.processOpData.singleDataTransferData.addressingMode = a64inst_PRE_INDEXED;
instr->data.SingleTransferData.processOpData.singleDataTransferData.a64inst_addressingModeData.indexedOffset = getOperandNumber(operands[1]);
} else if (operandCount == 1 || (!isOperandRegister(*operands[1]))) {
instr->data.SingleTransferData.processOpData.singleDataTransferData.addressingMode = a64inst_UNSIGNED_OFFSET;
if(operandCount > 1){
int offset = getOperandNumber(operands[1]);
instr->data.SingleTransferData.processOpData.singleDataTransferData.a64inst_addressingModeData.unsignedOffset = offset/8;
//NEED TO SCALE IMMEDIATE VALUE BASED ON REGISTER TYPE IN ASSEMBLER
}
} else {
if((isOperandRegister(*operands[0]) == 1)
&& (isOperandRegister(*operands[1]) == 1)){
//register
instr->data.SingleTransferData.processOpData.singleDataTransferData.addressingMode = a64inst_REGISTER_OFFSET;
instr->data.SingleTransferData.processOpData.singleDataTransferData.a64inst_addressingModeData.offsetReg = getOperandNumber(operands[1]);
}
}
}
static int parseRegisterType(char *operand) {
return operand[0] == 'x';
}
void parseDirective(a64inst_instruction *instr, char *tokens[]) {
static void parseDirective(a64inst_instruction *instr, char *tokens[]) {
char *intValue = tokens[1];
char *endptr;
if(strncmp(intValue, "0x", 2) == 0) {
@ -314,27 +155,28 @@ void parseDirective(a64inst_instruction *instr, char *tokens[]) {
}
void parseSingleTransfer(a64inst_instruction *instr, char *opcode, char *tokens[], int tokensCount) {
static void parseSingleTransfer(a64inst_instruction *instr, char *opcode, char *tokens[], int tokensCount) {
switch(instr->type){
case a64inst_SINGLETRANSFER:
instr->data.SingleTransferData.regType = parseRegisterType(tokens[1]);
instr->data.SingleTransferData.target = getOperandNumber(tokens[1]);
instr->data.SingleTransferData.regType = getRegisterType(tokens[1]);
instr->data.SingleTransferData.target = getRegister(tokens[1]);
break;
case a64inst_LOADLITERAL:
instr->data.SingleTransferData.regType = parseRegisterType(tokens[1]);
instr->data.SingleTransferData.target = getOperandNumber(tokens[1]);
instr->data.SingleTransferData.regType = getRegisterType(tokens[1]);
instr->data.SingleTransferData.target = getRegister(tokens[1]);
if(*tokens[2] =='#'){
//offset is immediate
int offset = getOperandNumber(tokens[1]);
instr->data.SingleTransferData.processOpData.loadLiteralData.offset = offset;
instr->data.SingleTransferData.processOpData.loadLiteralData.offset = getImmediate(tokens[2]);;
} else {
//offset is label
instr->data.SingleTransferData.processOpData.loadLiteralData.label = tokens[2];
//offset is literal, use symbol table and calculate difference
}
break;
default:
break;
@ -350,7 +192,7 @@ void parseBranch(a64inst_instruction *instr, char* opcode, char *operandList[])
instr->data.BranchData.processOpData.unconditionalData.label = operandList[1];
break;
case a64inst_REGISTER:
instr->data.BranchData.processOpData.registerData.src = getOperandNumber(operandList[1]);
instr->data.BranchData.processOpData.registerData.src = getRegister(operandList[1]);
break;
case a64inst_CONDITIONAL:
{
@ -381,13 +223,13 @@ void parseBranch(a64inst_instruction *instr, char* opcode, char *operandList[])
void parseDPImmediate(a64inst_instruction *inst, char *tokens[], int tokensCount) {
a64inst_DPImmediateData *data = &inst->data.DPImmediateData;
data->dest = getOperandNumber(tokens[1]);
data->regType = parseRegisterType(tokens[1]);
data->dest = getRegister(tokens[1]);
data->regType = getRegisterType(tokens[1]);
if (isStringIn(tokens[0], WIDE_MOV_OPCODES, 4)) {
if (containsString(tokens[0], WIDE_MOV_OPCODES, 4)) {
data->DPIOpType = a64inst_DPI_WIDEMOV;
data->processOp = indexStringIn(tokens[0], WIDE_MOV_OPCODES, 4);
data->processOpData.wideMovData.immediate = getOperandNumber(tokens[2]);
data->processOp = lastIndexOfString(tokens[0], WIDE_MOV_OPCODES, 4);
data->processOpData.wideMovData.immediate = getImmediate(tokens[2]);
if (tokensCount >= 4) {
ShiftData shData = *parseShift(tokens[3]);
data->processOpData.wideMovData.shiftScalar = shData.immediate;
@ -395,9 +237,9 @@ void parseDPImmediate(a64inst_instruction *inst, char *tokens[], int tokensCount
} else {
data->DPIOpType = a64inst_DPI_ARITHM;
data->processOp = indexStringIn(tokens[0], ARITHMETIC_OPCODES, 4);
data->processOpData.arithmData.src = getOperandNumber(tokens[2]);
data->processOpData.arithmData.immediate = getOperandNumber(tokens[3]);
data->processOp = lastIndexOfString(tokens[0], ARITHMETIC_OPCODES, 4);
data->processOpData.arithmData.src = getRegister(tokens[2]);
data->processOpData.arithmData.immediate = getImmediate(tokens[3]);
if (tokensCount >= 5) {
ShiftData shData = *parseShift(tokens[4]);
@ -411,16 +253,16 @@ void parseDPImmediate(a64inst_instruction *inst, char *tokens[], int tokensCount
void parseDPRegister(a64inst_instruction *inst, char *tokens[], int tokensCount) {
a64inst_DPRegisterData *data = &inst->data.DPRegisterData;
data->dest = getOperandNumber(tokens[1]);
data->regType = parseRegisterType(tokens[1]);
data->src1 = getOperandNumber(tokens[2]);
data->src2 = getOperandNumber(tokens[3]);
data->dest = getRegister(tokens[1]);
data->regType = getRegisterType(tokens[1]);
data->src1 = getRegister(tokens[2]);
data->src2 = getRegister(tokens[3]);
if (isStringIn(tokens[0], MULTIPLY_OPCODES, 4)) {
if (containsString(tokens[0], MULTIPLY_OPCODES, 4)) {
// Multiply
data->DPROpType = a64inst_DPR_MULTIPLY;
if (tokensCount >= 5) {
data->processOpData.multiplydata.summand = getOperandNumber(tokens[4]);
data->processOpData.multiplydata.summand = getRegister(tokens[4]);
data->processOpData.multiplydata.negProd = strcmp(tokens[0], "msub") == 0;
}
else {
@ -432,21 +274,21 @@ void parseDPRegister(a64inst_instruction *inst, char *tokens[], int tokensCount)
// Arithmetic/Logic
data->DPROpType = a64inst_DPR_ARITHMLOGIC;
if (isStringIn(tokens[0], ARITHMETIC_OPCODES, 4)) {
if (containsString(tokens[0], ARITHMETIC_OPCODES, 4)) {
// Arithmetic
data->processOp = indexStringIn(tokens[0], ARITHMETIC_OPCODES, 4);
data->processOp = lastIndexOfString(tokens[0], ARITHMETIC_OPCODES, 4);
data->processOpData.arithmLogicData.type = 1;
if(tokensCount == 5) {
//has a shift
int numTokens = 0;
char **shiftOperands = tokenise(tokens[4], &numTokens);
data->processOpData.arithmLogicData.shiftType = indexStringIn(shiftOperands[0], SHIFT_TYPE_OPCODES, 4);
data->processOpData.arithmLogicData.shiftAmount = getOperandNumber(shiftOperands[1]);
data->processOpData.arithmLogicData.shiftType = lastIndexOfString(shiftOperands[0], SHIFT_TYPE_OPCODES, 4);
data->processOpData.arithmLogicData.shiftAmount = getImmediate(shiftOperands[1]);
}
} else {
// Logic
int opcodeCategory = indexStringIn(tokens[0], LOGIC_OPCODES, 8);
int opcodeCategory = lastIndexOfString(tokens[0], LOGIC_OPCODES, 8);
switch(opcodeCategory/2){
case 0:
//and
@ -489,9 +331,102 @@ void parseDPRegister(a64inst_instruction *inst, char *tokens[], int tokensCount)
//has a shift
int numTokens = 0;
char **shiftOperands = tokenise(tokens[4], &numTokens);
data->processOpData.arithmLogicData.shiftType = indexStringIn(shiftOperands[0], SHIFT_TYPE_OPCODES, 4);
data->processOpData.arithmLogicData.shiftAmount = getOperandNumber(shiftOperands[1]);
data->processOpData.arithmLogicData.shiftType = lastIndexOfString(shiftOperands[0], SHIFT_TYPE_OPCODES, 4);
data->processOpData.arithmLogicData.shiftAmount = getImmediate(shiftOperands[1]);
}
}
}
}
/** Classifies the given opcode into the correct instruction type.
* Modifies instr to reflect the classification.
*/
static void classifyOpcode(char* opcode, a64inst_instruction *instr, char *tokens[], int *tokensCount) {
// First, if the opcode is an alias, convert it to the target instruction.
translateAlias(opcode, tokens, tokensCount);
if (containsString(opcode, BRANCH_OPCODES, 9)) {
instr->type = a64inst_BRANCH;
if (strcmp(opcode, "br") == 0) {
instr->data.BranchData.BranchType = a64inst_REGISTER;
} else if (strcmp(opcode, "b") == 0) {
instr->data.BranchData.BranchType = a64inst_UNCONDITIONAL;
} else {
instr->data.BranchData.BranchType = a64inst_CONDITIONAL;
}
} else if (containsString(opcode, SINGLE_TRANSFER_OPCODES, 2)) {
instr->type = a64inst_SINGLETRANSFER;
if (*tokens[2] == '[') {
instr->data.SingleTransferData.SingleTransferOpType = a64inst_SINGLE_TRANSFER_SINGLE_DATA_TRANSFER;
instr->data.SingleTransferData.processOpData.singleDataTransferData.transferType = strcmp(opcode, "ldr") == 0;
} else {
instr->type = a64inst_LOADLITERAL;
}
// DP Instruction.
// DP Register if the third operand is a register.
} else if (*tokensCount >= 4 && isRegister(tokens[3])) {
instr->type = a64inst_DPREGISTER;
} else {
instr->type = a64inst_DPIMMEDIATE;
}
}
/** Parses a shift string into a ShiftData struct.
*/
static ShiftData *parseShift(char *shift) {
char buffer[20];
strcpy(buffer, shift);
char *shiftType = strtok(buffer, " ");
char *shiftAmount = strtok(NULL, " ");
ShiftData *data = malloc(sizeof(ShiftData));
data->type = lastIndexOfString(shiftType, SHIFT_TYPE_OPCODES, 4);
SKIP_WHITESPACE(shiftAmount);
data->immediate = getImmediate(shiftAmount);
return data;
}
/** Parses the addressing mode of a single transfer instruction. (Not load literal)
*/
static void parseAddressingMode(a64inst_instruction *instr, char *tokens[], int tokenCount) {
assert(*tokens[2] == '[');
int operandCount = 0;
char *unsplitString = duplicateString(tokens[2]);
char **operands = tokeniseOperands(tokens[2], &operandCount);
int baseRegister = getRegister(operands[0]);
instr->data.SingleTransferData.processOpData.singleDataTransferData.base = baseRegister;
if (tokenCount >= 4) {
instr->data.SingleTransferData.processOpData.singleDataTransferData.addressingMode = a64inst_POST_INDEXED;
instr->data.SingleTransferData.processOpData.singleDataTransferData.a64inst_addressingModeData.indexedOffset = getImmediate(tokens[3]);
} else if(unsplitString[strlen(unsplitString)-1] == '!') {
instr->data.SingleTransferData.processOpData.singleDataTransferData.addressingMode = a64inst_PRE_INDEXED;
instr->data.SingleTransferData.processOpData.singleDataTransferData.a64inst_addressingModeData.indexedOffset = getImmediate(operands[1]);
} else if (operandCount == 1 || (!isRegister(operands[1]))) {
instr->data.SingleTransferData.processOpData.singleDataTransferData.addressingMode = a64inst_UNSIGNED_OFFSET;
if(operandCount > 1){
int offset = getImmediate(operands[1]);
instr->data.SingleTransferData.processOpData.singleDataTransferData.a64inst_addressingModeData.unsignedOffset = offset/8;
}
} else {
if((isRegister(operands[0]) == 1)
&& (isRegister(operands[1]) == 1)){
instr->data.SingleTransferData.processOpData.singleDataTransferData.addressingMode = a64inst_REGISTER_OFFSET;
instr->data.SingleTransferData.processOpData.singleDataTransferData.a64inst_addressingModeData.offsetReg = getRegister(operands[1]);
}
}
}

17
src/parser.h
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@ -1,6 +1,17 @@
/** @file parser.h
* @brief A function to parse ARMv8 assembly lines into an array of a special
* internal representation of instructions, a64inst_instruction.
*
* @author Ethan Dias Alberto
* @author Saleh Bubshait
*/
#include "a64instruction/a64instruction.h"
#define OPERAND_DELIMITER ", "
#define HALT_ASM_CMD "and x0, x0, x0\n"
/** @brief Parses a list of ARMv8 assembly lines into an array of a64inst_instruction.
*
* @param asmLines An array of strings, each string is an ARMv8 assembly line.
* @param lineCount The number of lines in the asmLines array.
* @return An array of a64inst_instruction representing the parsed instructions.
*/
a64inst_instruction *parse(char **asmLines, int lineCount);

173
src/string_util.c Normal file
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@ -0,0 +1,173 @@
/** @file string_util.c
* @brief This file contains the implementation of some string processing
* utility functions used in the assembler.
*
* @author Saleh Bubshait
*/
#include <string.h>
#include <ctype.h>
#include <stdbool.h>
#include <stdlib.h>
#include "string_util.h"
#include "global.h"
/************************************
* CONSTANTS
************************************/
static const char *SPECIAL_REGISTERS[] = {"sp", "xzr", "wzr"};
static const char *ZERO_REGISTER_ALIAS[] = {"xzr", "wzr"};
static const char *ALIAS_OPCODES[] = {"cmp", "cmn", "neg", "negs", "tst", "mvn", "mov"};
static char *ALIAS_TARGET_OPCODES[] = {"subs", "adds", "sub", "subs", "ands", "orn", "orr"};
/************************************
* FUNCTIONS
************************************/
char *trim(char *str) {
// Skip leading whitespace
while (isspace(*str)) {
str++;
}
// If the string is all whitespace
if (*str == '\0') {
return str;
}
// Skip trailing whitespace
char *end = str + strlen(str) - 1;
while (end > str && isspace(*end)) {
end--;
}
end[1] = '\0';
return str;
}
bool containsString(char *str, const char *arr[], int arrSize) {
for (int i = 0; i < arrSize; i++) {
if (strcmp(str, arr[i]) == 0) {
return true;
}
}
return false;
}
int lastIndexOfString(char *str, const char *arr[], int arrSize) {
for (int i = arrSize - 1; i >= 0; i--) {
if (strcmp(str, arr[i]) == 0) {
return i;
}
}
return -1;
}
char *duplicateString(char *str) {
char *newStr = malloc(strlen(str) + 1);
strcpy(newStr, str);
return newStr;
}
bool isRegister(char *str) {
SKIP_WHITESPACE(str);
if (str == NULL)
return false;
if (containsString(str, SPECIAL_REGISTERS, 3))
return true;
return tolower(str[0]) == 'x' || tolower(str[0]) == 'w';
}
int getRegister(char *str) {
SKIP_WHITESPACE(str);
if (containsString(str, ZERO_REGISTER_ALIAS, 2)) {
return ZERO_REGISTER;
}
return strtol(str + 1, NULL, 10);
}
int getImmediate(char *str) {
SKIP_WHITESPACE(str);
if (strlen(str) < 2) {
return 0;
}
if (str[0] != '#')
return 0;
str++; // skip #
if (strncmp(str, "0x", 2) == 0 || strncmp(str, "0X", 3) == 0) {
// Hex
return strtol(str + 2, NULL, 16);
} else {
// Decimal
return strtol(str, NULL, 10);
}
return 0;
}
int getRegisterType(char *str) {
SKIP_WHITESPACE(str);
return tolower(str[0]) == 'x';
}
/** @brief Translates an alias instruction into its target instruction.
* Note: This function modifies the input tokens array and the tokensCount.
* Assumes there is enough space in the tokens array to add the new tokens.
*
* @param opcode The opcode of the instruction.
* @param tokens The tokens of the instruction.
* @param tokensCount The number of tokens in the instruction.
*/
void translateAlias(char *opcode, char *tokens[], int *tokensCount) {
int aliasIndex = lastIndexOfString(opcode, ALIAS_OPCODES, 9);
if (aliasIndex == -1)
return;
// The instruction is one of the aliases, convert into the target.
char *targetOpcode = ALIAS_TARGET_OPCODES[aliasIndex];
// To correctly encode the zero register, which is either w31 or x31.
char *zeroReg = malloc(5 * sizeof(char));
*zeroReg = *tokens[1];
strcat(zeroReg, "31");
switch(aliasIndex) {
case 0: // cmp -> subs rzr, rn, <op2>
case 1: // cmn -> adds rzr, rn, <op2>
case 4: // tst -> ands rzr, rn, <op2>
// Convert from [instr] reg, <op2> to [instr] rzr, reg, <op2>
tokens[0] = targetOpcode;
tokens[4] = tokens[3];
tokens[3] = tokens[2];
tokens[2] = tokens[1];
tokens[1] = zeroReg;
(*tokensCount)++;
break;
case 2: // neg -> subs rd, rzr, <op2>
case 3: // negs -> subs rd, rzr, <op2>
case 5: // mvn -> orn rd, rzr, <op2>
case 6: // mov -> orr rd, rzr, rm
tokens[0] = targetOpcode;
tokens[4] = tokens[3];
tokens[3] = tokens[2];
tokens[2] = zeroReg;
(*tokensCount)++;
break;
default:
// Note, the multiply instructions are handled separately.
// See DPReg parsing.
break;
}
}

64
src/string_util.h Normal file
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@ -0,0 +1,64 @@
/** @file string_util.h
* @brief This file contains the implementation of some string processing
* utility functions used in the assembler.
*
* @author Saleh Bubshait
*/
/** @brief Skips whitespace characters in a string.
* @param ptr A pointer to the string to skip whitespace in.
*/
#define SKIP_WHITESPACE(ptr) do { while (isspace(*ptr)) { ptr++; } } while (0)
/** @brief Removes leading and trailing whitespace from a string.
* Note. This function modifies the input string.
* @param str The string to trim.
* @return A pointer to the first non-whitespace character in the string.
*/
char *trim(char *str);
/** @brief Checks if a string is in an array of strings.
*
* @param str The string to check.
* @param arr The array of strings to check against.
* @param arrSize The size of the array.
* @return True if the string is in the array, false otherwise.
*/
bool containsString(char *str, const char *arr[], int arrSize);
/** @brief Finds the last index of a string in an array of strings.
* Note: If multiple occurances of the string exist, the index of the last
* occurance is returned!
*
* @param str The string to find.
* @param arr The array of strings to search.
* @param arrSize The size of the array.
* @return The index of the last occurrence of the string in the array, or -1 if not found.
*/
int lastIndexOfString(char *str, const char *arr[], int arrSize);
/** @brief Duplicates a string.
* Note: The caller is responsible for freeing the returned string.
*
* @param str The string to duplicate.
* @return A pointer to the duplicated string.
*/
char *duplicateString(char *str);
/** @brief Checks if a string represents an ARMv8 register.
* A string is considered a register if it is:
* - A general purpose register (x0-x30 or w0-w30)
* - A special register (sp, xzr, wzr)
*
* @param str The string to check.
* @return True if the string is a register, false otherwise.
*/
bool isRegister(char *str);
int getRegister(char *str);
int getImmediate(char *str);
int getRegisterType(char *str);
void translateAlias(char *opcode, char *tokens[], int *tokensCount);

8
src/symboltable.c
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@ -1,3 +1,11 @@
/** @file symboltable.c
* @brief An Abstract Data Type (ADT) for a symbol table, an array of
* label-address pairs. Labels are strings and addresses are unsigned integers.
* (uint32_t). The symbol table is implemented as a dynamic array.
*
* @author Saleh Bubshait
*/
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

49
src/symboltable.h
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@ -1,3 +1,11 @@
/** @file symboltable.h
* @brief An Abstract Data Type (ADT) for a symbol table, an array of
* label-address pairs. Labels are strings and addresses are unsigned integers.
* (uint32_t). The symbol table is implemented as a dynamic array.
*
* @author Saleh Bubshait
*/
#include <stdbool.h>
#include <stdint.h>
#include <stdio.h>
@ -7,21 +15,56 @@
typedef uint32_t address;
/** An entry in the symbol table, a label-address pair.
*/
typedef struct {
char *label;
address address;
} symbol_table_map;
/** The symbol table ADT.
*/
typedef struct {
symbol_table_map* table;
int size;
int capacity;
symbol_table_map* table; // entries
int size; // number of entries
int capacity; // size of the table. capacity >= size
} symbol_table;
/** @brief Initializes a new symbol table.
*
* @return A pointer to the new symbol table.
*/
symbol_table *st_init(void);
/** @brief Inserts a new label-address pair to the symbol table.
* Grows the table if it is full. If the label already exists in the table,
* another entry with the same label is inserted (for performance).
*
* @param st A pointer to the target symbol table.
* @param label The label to insert.
* @param addr The address to insert.
*/
void st_insert(symbol_table *st, char *label, address addr);
/** @brief Checks if a label exists in the symbol table.
*
* @param st A pointer to the target symbol table.
* @param label The label to check.
* @return True if the label exists in the table, false otherwise.
*/
bool st_contains(symbol_table *st, char *label);
/** @brief Gets the address of a label in the symbol table.
* st_contains should be called before calling this function!
*
* @param st A pointer to the target symbol table.
* @param label The label to get the address of.
* @return The address of the label in the table.
*/
address st_get(symbol_table *st, char *label);
/** @brief Frees the memory allocated for the symbol table.
*
* @param st A pointer to the target symbol table.
*/
void st_free(symbol_table *st);

99
src/tokeniser.c
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@ -1,33 +1,23 @@
// Tokeniser.c
/** @file tokeniser.c
* @brief Functions to tokenise lines of assembly and operand strings.
*
* @author Saleh Bubshait
*/
#include <assert.h>
#include <ctype.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <stdbool.h>
#include "tokeniser.h"
#include "string_util.h"
#define MAX_TOKEN_COUNT 5
#define MAX_OPERAND_COUNT 4
#define MAX_TOKEN_COUNT 6
#define MAX_OPERAND_COUNT 5
#define OPERAND_DELIMITER ", "
char *trim(char *str) {
while (isspace(*str)) {
str++;
}
if (*str == '\0') {
return str;
}
char *end = str + strlen(str) - 1;
while (end > str && isspace(*end)) {
end--;
}
end[1] = '\0';
return str;
}
#define OPEN_BRACKET '['
#define CLOSE_BRACKET ']'
char **tokenise(char *line, int *numTokens) {
char **tokens = malloc(MAX_TOKEN_COUNT * sizeof(char *));\
@ -46,36 +36,22 @@ char **tokenise(char *line, int *numTokens) {
char *operandStart = strtok(NULL, "");
if (operandStart == NULL) {
// No operands. Return the instruction token.
// No operands. Return the first (opcode) token.
return tokens;
}
bool inBracket = false;
char *currentToken = operandStart;
SKIP_WHITESPACE(operandStart);
for (char *c = operandStart; *c != '\0'; ++c) {
if (*c == '[' || *c == '{') {
inBracket = true;
} else if (*c == ']' || *c == '}') {
inBracket = false;
// Use tokeniseOperands to tokenise the operands
int operandTokensCount = 0;
char **operandTokens = tokeniseOperands(operandStart, &operandTokensCount);
for (int i = 0; i < operandTokensCount; i++) {
tokens[(*numTokens)++] = operandTokens[i];
}
if (*c == ',' && !inBracket) {
*c = '\0';
tokens[(*numTokens)++] = currentToken;
currentToken = c + 1;
while (*currentToken == ' ') {
currentToken++;
}
}
}
if (*currentToken != '\0') {
tokens[*numTokens] = currentToken;
(*numTokens)++;
}
free(operandTokens);
return tokens;
}
@ -86,42 +62,43 @@ char **tokeniseOperands(char *line, int *numTokens) {
exit(EXIT_FAILURE);
}
if (*line == '[') {
SKIP_WHITESPACE(line);
// Remove leading and trailing brackets if they exist
if (*line == OPEN_BRACKET) {
line++; // skip '['
line[strlen(line) - 1] = '\0'; // remove ']'
} else if (*line == '{') {
line++; // skip '{'
line[strlen(line) - 1] = '\0'; // remove '}'
char *end = line + strlen(line) - 1;
while (end > line && *end != CLOSE_BRACKET) {
end--;
}
if (*end == CLOSE_BRACKET) {
*end = '\0';
}
}
line = trim(line);
*numTokens = 0;
bool inBracket = false;
char *currentToken = line;
for (char *c = line; *c != '\0'; ++c) {
if (*c == '[' || *c == '{') {
if (*c == '[') {
inBracket = true;
} else if (*c == ']' || *c == '}') {
} else if (*c == ']') {
inBracket = false;
}
if (*c == ',' && !inBracket) {
*c = '\0';
tokens[(*numTokens)++] = currentToken;
currentToken = c + 1;
while (*currentToken == ' ') {
currentToken++;
}
currentToken = c + 1; // skip the comma
SKIP_WHITESPACE(currentToken);
}
}
if (*currentToken != '\0') {
tokens[*numTokens] = currentToken;
if (tokens[*numTokens][strlen(tokens[*numTokens]) - 1] == '\n') {
tokens[*numTokens][strlen(tokens[*numTokens]) - 1] = '\0';
}
(*numTokens)++;
}

26
src/tokeniser.h Normal file
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@ -0,0 +1,26 @@
/** @file tokeniser.h
* @brief Functions to tokenise lines of assembly and operand strings.
*
* @author Saleh Bubshait
*/
/** @brief Tokenises a line of assembly code. The first two tokens are separated
* by a space, and the rest are separated by commas.
* e.g., "add x1, x2, x3" -> ["add", "x1", "x2", "x3"]. Handles and skips any
* whitespaces, e.g., " add x1, x2,#4 " -> ["add", "x1", "x2", "#4"].
* @param line The line to tokenise.
* @param numTokens A pointer to an integer to store the number of tokens.
* @return An array of strings containing the tokens.
*/
char **tokenise(char *line, int *numTokens);
/** @brief Tokenises the operands of an instruction. The operands are separated
* by commas. Handles and skips any whitespaces, e.g., "x1, x2, #4" -> ["x1", "x2", "#4"].
* If the line starts with a bracket, it is removed and the closing bracket.
* Note. It also removes anything after the brackets, for example:
* "[x1, x2, #4]!" -> ["x1", "x2", "#4"].
* @param line The line to tokenise.
* @param numTokens A pointer to an integer to store the number of tokens.
* @return An array of strings containing the tokens.
*/
char **tokeniseOperands(char *line, int *numTokens);