rvemu

commit b6f38b53eb40e2eab52f93ca2b5bd2a5f1a27aa9
parent 50e9877a99f750e157f402ab7cfefb35f06514a9
Author: Michail Konstantinos Dimopoulos <mk@mcdim.xyz>
Date:   Thu, 27 Aug 2026 05:43:30 +0300

B-type complete

Diffstat:
M
main.c
 | 
96
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++-------------

1 file changed, 81 insertions(+), 15 deletions(-)
diff --git a/main.c b/main.c
@@ -488,19 +488,49 @@ void exec_btype(cpu_state_t *cpu, uint32_t inst, uint8_t *mem) {
 	printf("\n");
 	/*********/
 
+	int jump = 0;
 	switch (b.funct3) {
 	case 0x0:
-		if (cpu->x[b.rs1] == cpu->x[b.rs2]) {
-			uint32_t target;
-			if (get_valid_branch_target(cpu->pc, b.imm, &target) != 0) {
-				//fprintf(stderr, "Illegal branch target\n");
-				/**/fprintf(stderr, "Illegal BEQ target: pc=%" PRIu32 ", offset=%" PRId32 "\n", cpu->pc, b.imm);
-				return;
-			}
-			cpu->pc = target;
-		} else {
-			cpu->pc += 4;
+		if (cpu->x[b.rs1] == cpu->x[b.rs2])
+			jump = 1;
+		break;
+	case 0x1:
+		if (cpu->x[b.rs1] != cpu->x[b.rs2])
+			jump = 1;
+		break;
+	case 0x4:
+		if ((int32_t)cpu->x[b.rs1] < (int32_t)cpu->x[b.rs2])
+			jump = 1;
+		break;
+	case 0x5:
+		if ((int32_t)cpu->x[b.rs1] >= (int32_t)cpu->x[b.rs2])
+			jump = 1;
+		break;
+	case 0x6:
+		if (cpu->x[b.rs1] < cpu->x[b.rs2])
+			jump = 1;
+		break;
+	case 0x7:
+		if (cpu->x[b.rs1] >= cpu->x[b.rs2])
+			jump = 1;
+		break;
+	default:
+		fprintf(stderr, "Illegal funct3\n");
+		return;
+	}
+
+	if (jump == 1) {
+		uint32_t target;
+		if (get_valid_branch_target(cpu->pc, b.imm, &target) != 0)
+		{
+			fprintf(stderr, "Illegal branch target: pc=%"
+			        PRIu32 ", offset=%" PRId32 "\n",
+				cpu->pc, b.imm);
+			return;
 		}
+		cpu->pc = target;
+	} else {
+		cpu->pc += 4;
 	}
 
 }
@@ -509,11 +539,19 @@ void
 load_program(uint8_t *mem)
 {
 	/* PROGRAM */
+
+	/*uint32_t arr[] = {
+		0x500193,  // addi x3, x0, 5
+		0x600093,  // addi x1, x0, 6
+		0x118263,  // beq x3, x1. +4
+		0x728263   // beq x5, x7, +4
+	}; */
+
 	uint32_t arr[] = {
-		0x500193, // addi x3, x0, 5
-		0x600093, // addi x1, x0, 6
-		0x118263, // beq x3, x1. +4
-		0x728263  // beq x5, x7, +4
+		0x00500193,  // addi x3, x0, 5
+		0x00600093,  // addi x1, x0, 6
+		0x00118263,  // beq x3, x1. +4
+		0xfe728ae3 //   beq x5, x7, -12 -> addr 0
 	};
 	size_t len = sizeof(arr) / sizeof(arr[0]);
 
@@ -580,7 +618,6 @@ int main() {
 		    strncmp(line, "step", 4) == 0  ||
 		    strncmp(line, "n", 1) == 0 ||
 		    strncmp(line, "next", 4) == 0) {
-			//if (i >= len) return 0;
 
 			uint32_t inst = make_instruction(mem, cpu.pc);
 
@@ -625,3 +662,32 @@ int main() {
 
 	return 0;
 }
+
+/*
+int main() {
+	init_opcode_table();
+
+	cpu_state_t cpu = {0};
+
+	uint8_t mem[MEMSIZE] = {0};
+
+	load_program(mem);
+	
+	while (1) {
+		uint32_t inst = make_instruction(mem, cpu.pc);
+
+		uint16_t opcode = inst & 127;
+		exec_fn fn = opcode_table[opcode];
+
+		if (!fn) {
+			//illegal(NULL, inst);
+			fprintf(stderr, "Illegal opcode\n");
+			return EXIT_FAILURE;
+		}
+
+		fn(&cpu,inst,mem);
+	}
+
+	return 0;
+}
+*/