Restructured the Project

1 files changed, 240 insertions, 0 deletions

diff --git a/instruction.c b/instruction.c
new file mode 100644
index 0000000..a5fe208
--- /dev/null
+++ b/instruction.c
@@ -0,0 +1,240 @@
+#include "qdme.h"
+#include "instruction.h"
+#include <string.h>
+#include <stdio.h>
+#include <stdlib.h>
+
+/* InstFetch: Fetch the next instruction from memory into the given
+ * instruction */
+void InstFetch(inst_t *inst) {
+	uint32_t value = 0;
+	memcpy(&value, memory + pc, WORD_SIZE);
+	switch ((value & 0xFC000000) >> 26) {
+		case 0:
+			inst->type = RTYPE;
+			inst->r.op = (value & 0xFC000000) >> 26;
+			inst->r.rs = (value & 0x03E00000) >> 21;
+			inst->r.rt = (value & 0x001F0000) >> 16;
+			inst->r.rd = (value & 0x0000F800) >> 11;
+			inst->r.shamt = (value & 0x000007C0) >> 6;
+			inst->r.func = value & 0x0000002F;
+			break;
+		case 2:
+		case 3:
+			inst->type = JTYPE;
+			inst->j.op = (value & 0xFC000000) >> 26;
+			inst->j.addr = value & 0X03FFFFFF;
+			break;
+		default:
+			inst->type = ITYPE;
+			inst->i.op = (value & 0xFC000000) >> 26;
+			inst->i.rs = (value & 0x03E00000) >> 21;
+			inst->i.rt = (value & 0x001F0000) >> 16;
+			inst->i.imm = value & 0x0000FFFF;
+			break;
+	}
+	if (inst->value == 0) {
+		inst->type = NOP;
+	}
+	pc += WORD_SIZE;
+}
+
+static void Syscall(void) {
+	char c, *s;
+	switch (regFile[V0]) {
+		case 1:	// print integer
+			printf("%d", regFile[A0]);
+			break;
+		case 2:	// print float
+			break;
+		case 3:	// print double
+			break;
+		case 4:	// print string
+			printf("%s", memory + regFile[A0]);
+			break;
+		case 5:	// read integer
+			scanf("%d", (int *)regFile + V0);
+			break;
+		case 6:	// read float
+			break;
+		case 7:	// read double
+			break;
+		case 8:	// read string
+			s = (char *)calloc(regFile[A0], sizeof(char));
+			fgets(s, regFile[A0], stdin);
+			memcpy(memory + regFile[A1], s, regFile[A0]);
+			free(s);
+			break;
+		case 9:	// sbrk
+			break;
+		case 10:	//exit
+			exitStatus = 0;
+			run = false;
+			break;
+		case 11:	// print char
+			printf("%c", regFile[A0]);
+			break;
+		case 12:	// read char
+			c = 0;
+			scanf("%c", &c);
+			regFile[V0] = c;
+			break;
+		case 13:	// open file
+			break;
+		case 14:	// read from file
+			break;
+		case 15:	// write to file
+			break;
+		case 16:	// close file
+			break;
+		case 17:	// exit2
+			exitStatus = regFile[A0];
+			run = false;
+			break;
+	}
+}
+
+/* ExecRtype: Execute a given R-Type instruction */
+static void ExecRtype(const inst_t inst) {
+	rtype_t r = inst.r;
+	uint32_t a = regFile[r.rs], b = regFile[r.rt];
+	uint64_t mult = 0;
+	switch (r.func) {
+		case 32: // add
+			regFile[r.rd] = (signed)a + (signed)b;
+			break;
+		case 33: // addu
+			regFile[r.rd] = a + b;
+			break;
+		case 36: // and
+			regFile[r.rd] = a & b;
+			break;
+		case 37: // or
+			regFile[r.rd] = a | b;
+			break;
+		case 42: // slt
+			regFile[r.rd] = (signed)a < (signed)b;
+			break;
+		case 43: // sltu
+			regFile[r.rd] = a < b;
+			break;
+		case 34: // sub
+			regFile[r.rd] = (signed)a - (signed)b;
+			break;
+		case 35: // subu
+			regFile[r.rd] = a - b;
+			break;
+		case 38: // xor
+			regFile[r.rd] = a ^ b;
+			break;
+		case 0: // sll
+			regFile[r.rd] = b << r.shamt;
+			break;
+		case 3: // sra
+			regFile[r.rd] = (signed)b >> r.shamt;
+			break;
+		case 2: // srl
+			regFile[r.rd] = b >> r.shamt;
+			break;
+		case 26: // div
+			hi = (signed)a % (signed)b;
+			lo = (signed)a / (signed)b;
+			break;
+		case 27: // divu
+			hi = a % b;
+			lo = a / b;
+			break;
+		case 24: // mult
+			mult = (signed)a * (signed)b;
+			hi = (0xFFFFFFFF00000000 & mult) >> 32;
+			lo = 0x00000000FFFFFFFF & mult;
+			break;
+		case 25: // multu
+			mult = a * b;
+			hi = (0xFFFFFFFF00000000 & mult) >> 32;
+			lo = 0x00000000FFFFFFFF & mult;
+			break;
+		case 16: // MFHI
+			regFile[r.rd] = hi;
+			break;
+		case 18: // MFLO
+			regFile[r.rd] = lo;
+			break;
+		case 17: // MTHI
+			hi = regFile[r.rs];
+			break;
+		case 19: // MTLO
+			lo = regFile[r.rs];
+			break;
+		case 9: // jalr
+			regFile[r.rd] = pc;
+			/* Intentional Fall Through */
+		case 8: // jr
+			pc = a;
+			break;
+		case 12: // syscall
+			Syscall();
+			break;
+	}
+}
+
+/* InstExec: Execute a given instruction */
+void InstExec(const inst_t inst) {
+	if (inst.type == NOP) {
+		return;
+	}
+	int16_t imm = inst.i.imm;
+	int32_t a = regFile[inst.i.rs];
+	switch (inst.j.op) {
+		case 0: // R-type instruction
+			ExecRtype(inst);
+			break;
+		case 3: // jal
+			regFile[RA] = pc;
+			/* intentional fall through */
+		case 2: // j
+			pc = (0xF0000000 & pc ) | (signed)inst.j.addr;
+			break;
+		case 4: // beq
+			pc = (regFile[inst.i.rs] == regFile[inst.i.rt]) ? pc + 4 +
+				imm : pc;
+			break;
+		case 5: // bne
+			pc = (regFile[inst.i.rs] != regFile[inst.i.rt]) ? pc + 4 +
+				imm : pc;
+			break;
+		case 8: // addi
+			regFile[inst.i.rt] = a + imm;
+			break;
+		case 9: // addiu
+			regFile[inst.i.rt] = (unsigned)a + imm;
+			break;
+		case 12: // andi
+			regFile[inst.i.rt] = a & imm;
+			break;
+		case 13: // ori
+			regFile[inst.i.rt] = a | imm;
+			break;
+		case 14: // xori
+			regFile[inst.i.rt] = a ^ imm;
+			break;
+		case 10: // slti
+			regFile[inst.i.rt] = a < imm;
+			break;
+		case 11: // sltiu
+			regFile[inst.i.rt] = (unsigned)a < (uint16_t)imm;
+			break;
+		case 15: // lui
+			regFile[inst.i.rt] = imm << 16;
+			break;
+		case 35: // lw
+			memcpy(regFile + inst.i.rt, memory + regFile[inst.i.rs] + imm,
+					WORD_SIZE);
+			break;
+		case 43: // sw
+			memcpy(memory + regFile[inst.i.rs] + imm, regFile + inst.i.rt,
+					WORD_SIZE);
+			break;
+	}
+}
+