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Commit 6fc918d8 authored by sea19's avatar sea19
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Emulate almost complete

parent 0e185016
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src/emulate.c
View file @ 6fc918d8
......@@ -27,7 +27,7 @@ typedef struct arm_state {
int n, z, c, v;
} armstate;
void armstate_init(armstate *state, unsigned int *objectCode) {
void armstate_init(armstate *state) {
/* zero out all arm state */
state->n = 0;
state->z = 0;
......@@ -38,7 +38,7 @@ void armstate_init(armstate *state, unsigned int *objectCode) {
state->regs[i] = 0;
}
state -> memory = objectCode;
state->memory = calloc(STACK_SIZE, sizeof(int));
}
char *printenum(type t) { //Testing
......@@ -114,7 +114,7 @@ void findOpcode(decoded *decodedInstr, unsigned int instruction) {
// next_instruction_condition_check
int do_next_instruction(decoded *decodedInstr, armstate *state){
unsigned int cond = decodedInstr -> condition;
unsigned int cond = decodedInstr->condition;
int run_command;
if ((cond == 0) && (state->z == 1 )) { // cond in decimal?
run_command = 1;
......@@ -320,6 +320,7 @@ void add_instr(decoded *decodedInstr, armstate *state){
state -> z = 0;
}
}
free(decodedDp);
}
void tst_instr(decoded *decodedInstr, armstate *state){
......@@ -341,6 +342,7 @@ void tst_instr(decoded *decodedInstr, armstate *state){
state -> z = 0;
}
}
free(decodedDp);
}
void teq_instr(decoded *decodedInstr, armstate *state){
......@@ -358,6 +360,7 @@ void teq_instr(decoded *decodedInstr, armstate *state){
state -> z = 0;
}
}
free(decodedDp);
}
void cmp_instr(decoded *decodedInstr, armstate *state){
......@@ -379,6 +382,7 @@ void cmp_instr(decoded *decodedInstr, armstate *state){
state -> z = 0;
}
}
free(decodedDp);
}
void orr_instr(decoded *decodedInstr, armstate *state){
......@@ -423,7 +427,8 @@ void single_data_transfer_instr(decoded *decodedInstr, armstate *state){
unsigned int iw, immediate, offset, p_index, up_bit, load_bit, rn, rd;
unsigned int data;
iw = decodedInstr -> bit0to25;
iw = decodedInstr->bit0to25;
immediate = (iw >> 25) & 0b1;//0 - 24 bits 没了(第二十五位
p_index = (iw >> 24) & 0b1;
up_bit = (iw >> 23) & 0b1;
......@@ -438,27 +443,32 @@ void single_data_transfer_instr(decoded *decodedInstr, armstate *state){
// Operand2 is a register, return the value of offset / op2
val_reg_last12bits(decodedInstr, &offset, state);
}
if(load_bit == 1) {
data = state->memory[rn];
state->regs[rn] = data;
}
if(p_index == 1){
if(up_bit == 1){
state -> regs[rn] += offset;
data = offset + state->regs[rn];
} else{
state -> regs[rn] -= offset;
data = state->regs[rn] - offset;
}
state -> regs[rd] = state -> regs[rn];
} else{
state -> regs[rd] = state -> regs[rn];
if(up_bit == 1){
state -> regs[rn] += offset;
data = state->regs[rn];
state->regs[rn] += offset;
} else{
state -> regs[rn] -= offset;
data = state->regs[rn];
state->regs[rn] -= offset;
}
}
if(load_bit == 1) {
char *byteMem = (char *) state->memory;
int *memAdd = (int *)(byteMem + data);
state->regs[rd] = *memAdd;
} else {
/*char *byteMem = state->memory;
int *memAdd = byteMem + data;
*memAdd = state->regs[rd];*/
}
}
void multiply_instr(decoded *decodedInstr, armstate *state){
......@@ -466,10 +476,10 @@ void multiply_instr(decoded *decodedInstr, armstate *state){
iw = decodedInstr -> bit0to25;;
acc = (iw >> 21) & 0b1;
set = (iw >> 20) & 0b1;
rd = (iw >> 16) & 0xF;
rn = (iw >> 12) & 0xF;
rs = (iw >> 8) & 0xF;
rm = iw & 0xF;
rd = (iw >> 16) & 0xf;
rn = (iw >> 12) & 0xf;
rs = (iw >> 8) & 0xf;
rm = iw & 0xf;
if(acc == 1){
state -> regs[rd] = state -> regs[rm] * state -> regs[rs] + state -> regs[rn];
......@@ -492,11 +502,15 @@ void multiply_instr(decoded *decodedInstr, armstate *state){
//not sure about branch execution///////////////
void branch_instr(decoded *decodedInstr, armstate *state){
signed int offset;
unsigned int iw = decodedInstr -> bit0to25;
unsigned int iw = decodedInstr->bit0to25;
// shifted left 2 bits, sign extended to 32 bits??????????????
offset = ((signed) (iw & 0xFFFFFF)) << 2;
state -> regs[PC] += offset;
offset = (iw & 0x00ffffff) << 2;
int sign = (iw >> 23) & 0b1;
if (sign == 1) {
offset = offset | 0xff000000;
}
state->regs[PC] += offset;
}
......@@ -506,17 +520,21 @@ unsigned int fetch(unsigned int *objectcode, unsigned int programCounter) {
void decode(unsigned int instruction, decoded *decodedInstr) {
unsigned int bit26and27 = (instruction >> 26) & 0b11;
decodedInstr->condition = (instruction >> 28) & 0xf;
decodedInstr->bit0to25 = (instruction) & 0x3ffffff;
if (bit26and27 == 0) {
findOpcode(decodedInstr, instruction);
if (((instruction >> 22) & 0xf) == 0 && ((instruction >> 4) & 0xf) == 9) {
decodedInstr->type = multiply;
} else {
findOpcode(decodedInstr, instruction);
}
} else if (bit26and27 == 1) {
decodedInstr->type = singledata;
} else if (bit26and27 == 2) {
decodedInstr->type = branch;
}
}
void execute(decoded *decodedInstr, armstate *state){
......@@ -566,11 +584,35 @@ void execute(decoded *decodedInstr, armstate *state){
state->regs[PC] += 4;
}
void startCycle(unsigned int *objectcode, armstate *state) {
void bigToLittleEndian(armstate *state) {
int temp;
for (int i = 0; i < NREGS - 2; i++) {
temp = state->regs[i];
state->regs[i] = (temp & 0xff) << 24 | (temp & 0xff00) << 8 | (temp & 0xff0000) >> 8 | (temp & 0xff000000) >> 24;
}
for (int j = 0; j < STACK_SIZE; j++) {
temp = state->memory[j];
state->memory[j] = (temp & 0xff) << 24 | (temp & 0xff00) << 8 | (temp & 0xff0000) >> 8 | (temp & 0xff000000) >> 24;
}
}
void printResult(armstate *state) {
printf("Registers:\n");
for (int i = 0; i < 13; i++) {
printf("$%d : %d (%x)\n", i, state->regs[i], state->regs[i]);
}
printf("PC : %d (%x)\n", state->regs[PC], state->regs[PC]);
printf("CPSR : %d (%x)\n", state->regs[16], state->regs[16]);
printf("Non-zero memory:\n");
}
void startCycle(armstate *state) {
unsigned int *pc = &(state->regs[PC]); //pc takes the value of the program counter
unsigned int fetched;
decoded *decodedInstr = (decoded *) calloc(1, sizeof(decoded));
bool finished = false;
unsigned int *objectcode = state->memory;
while(!finished) {
if (*pc == 0) {
......@@ -582,6 +624,10 @@ void startCycle(unsigned int *objectcode, armstate *state) {
*pc = *pc + 4;
} else {
execute(decodedInstr, state);
if (decodedInstr->type == branch && do_next_instruction(decodedInstr, state)) {
fetched = fetch(objectcode, *pc/4);
*pc += 4;
}
decode(fetched, decodedInstr);
fetched = fetch(objectcode, *pc/4);
*pc = *pc + 4;
......@@ -590,46 +636,43 @@ void startCycle(unsigned int *objectcode, armstate *state) {
}
}
printf("fetched instruction: %d\n", fetched);
printf("decoded type: %s\n", printenum(decodedInstr->type)); //Used for testing
for(int i = 0; i < NREGS; i++){
printf("register[%d]: %d\n", i, state -> regs[i]);
}
state->regs[16] = state->n << 31 | state->z << 30 | state->c << 29 | state->v << 28;
//printf("fetched instruction: %x\n", fetched);
//printf("decoded type: %s\n", printenum(decodedInstr->type)); //Used for testing
}
printResult(state);
free(decodedInstr);
} //pipeline
unsigned int *readFile(char *filename) {
unsigned int *objectCode = calloc(16384, sizeof(int));
void readFile(char *filename, unsigned int *memory) {
//Creates a pointer with allocated space of 64KB
int i = 0;
FILE *ptr = fopen(filename, "rb"); //Opens file "filename" to be read as a binary file
assert(ptr != NULL); //Checks the file has been read
while (!feof(ptr)) {
fread(objectCode + i, 4, 1, ptr);
fread(memory + i, 4, 1, ptr);
//Stores the binary data in the files into the array objectCode
i++;
}
fclose(ptr); //Closes file "filename"
return objectCode;
} //loader
int main(int argc, char **argv) {
unsigned int *objectcode = calloc(STACK_SIZE, sizeof(int));
//unsigned int registers[NREGS];
armstate *state = (armstate *) calloc(1, sizeof(armstate));
armstate_init(state, objectcode); // &??????????
armstate_init(state); // &??????????
assert(argc == 2);
objectcode = readFile(argv[1]);
readFile(argv[1], state->memory);
startCycle(objectcode, state); //???????
startCycle(state); //???????
free(objectcode);
free(state->memory);
free(state);
return EXIT_SUCCESS;
}
......
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