rvemu

commit 1b0c03d3ec03d206e74c17c7308f581f44332411
parent bcb8d4b9f6383baa8d150ef73f79e67280049a29
Author: Michail Konstantinos Dimopoulos <mk@mcdim.xyz>
Date:   Thu,  3 Sep 2026 23:38:06 +0300

Added fence

Diffstat:
M
disasm.c
 | 
16
++++++++++++++++
M
main.c
 | 
30
++++++++++++++++++++++++++----

2 files changed, 42 insertions(+), 4 deletions(-)
diff --git a/disasm.c b/disasm.c
@@ -261,6 +261,21 @@ disasm_itype_control(uint32_t inst)
 
 }
 
+static void
+disasm_itype_fence(uint32_t inst)
+{
+	itype_t i;
+	decode_itype(&i, inst);
+
+	if (i.funct3 != 0x0) {
+		puts("Illegal instruction");
+		return;
+	}
+
+	puts("fence");
+	return;
+}
+
 typedef void (*disasm_fn)(uint32_t inst);
 
 static disasm_fn opcode_table[128];
@@ -273,6 +288,7 @@ init_opcode_table(void)
         opcode_table[0x03] = disasm_itype_loads;
         opcode_table[0x67] = disasm_itype_jalr;
         opcode_table[0x73] = disasm_itype_control;
+        opcode_table[0x0f] = disasm_itype_fence;
         opcode_table[0x23] = disasm_stype;
         opcode_table[0x63] = disasm_btype;
         opcode_table[0x6f] = disasm_jtype;
diff --git a/main.c b/main.c
@@ -410,7 +410,9 @@ static void exec_jtype(cpu_state_t *cpu, uint32_t inst, uint8_t *mem) {
 	}
 }
 
-static void exec_utype(cpu_state_t *cpu, uint32_t inst, uint8_t *mem) {
+static void
+exec_utype(cpu_state_t *cpu, uint32_t inst, uint8_t *mem)
+{
 	(void)mem; /* suppressing unused parameters warning */
 	utype_t u;
 	decode_utype(&u, inst);
@@ -422,7 +424,8 @@ static void exec_utype(cpu_state_t *cpu, uint32_t inst, uint8_t *mem) {
 }
 
 static void
-exec_utype_auipc(cpu_state_t *cpu, uint32_t inst, uint8_t *mem) {
+exec_utype_auipc(cpu_state_t *cpu, uint32_t inst, uint8_t *mem)
+{
 	(void)mem; /* suppressing unused parameters warning */
 	utype_t u;
 	decode_utype(&u, inst);
@@ -459,6 +462,21 @@ exec_itype_control(cpu_state_t *cpu, uint32_t inst, uint8_t *mem)
 }
 
 static void
+exec_itype_fence(cpu_state_t *cpu, uint32_t inst, uint8_t *mem)
+{
+	(void)mem; /* suppressing unused parameters warning */
+	itype_t i;
+	decode_itype(&i, inst);
+
+	if (i.funct3 != 0x0) {
+		raise_trap(cpu, TRAP_ILLEGAL_INSTRUCTION, inst);
+		return;
+	}
+
+	cpu->pc += 4;
+}
+
+static void
 load_program(uint8_t *mem)
 {
 	/* PROGRAM */
@@ -467,6 +485,8 @@ load_program(uint8_t *mem)
 		0x00600093,	// addi x1, x0, 6
 		0xaaaaa3b7,	// lui x7, 0xaaaaa		-> rd:aaaaa000
 		0x00001397,	// auipc x7 0x1 		-> rd 1008
+		0x00000013,	// nop
+		0x0ff0000f,	// fence
 		0x00100073,	// ebreak
 	};
 	size_t len = sizeof(arr) / sizeof(arr[0]);
@@ -508,6 +528,7 @@ init_opcode_table(void)
         opcode_table[0x03] = exec_itype_loads;
         opcode_table[0x67] = exec_itype_jalr;
         opcode_table[0x73] = exec_itype_control;
+        opcode_table[0x0f] = exec_itype_fence;
         opcode_table[0x23] = exec_stype;
         opcode_table[0x63] = exec_btype;
         opcode_table[0x6f] = exec_jtype;
@@ -516,7 +537,9 @@ init_opcode_table(void)
 }
 /***/
 
-int main() {
+int
+main()
+{
 	init_opcode_table();
 
 	cpu_state_t cpu = {0};
@@ -574,7 +597,6 @@ int main() {
 				case TRAP_NONE:
 					printf("No trap cause\n");
 					break;
-					
 				}
 				return EXIT_FAILURE;
 			}