rvemu

commit bcb8d4b9f6383baa8d150ef73f79e67280049a29
parent 2573410cb02d2f261c9d8b0c7422e0353c994af2
Author: Michail Konstantinos Dimopoulos <mk@mcdim.xyz>
Date:   Thu,  3 Sep 2026 20:06:31 +0300

Added ebreak and ecall

Diffstat:
M
Makefile
 | 
7
-------
M
disasm.c
 | 
26
++++++++++++++++++++++++++
M
main.c
 | 
41
++++++++++++++++++++++++++++++++++-------
M
trap.h
 | 
2
+-

4 files changed, 61 insertions(+), 15 deletions(-)
diff --git a/Makefile b/Makefile
@@ -4,10 +4,3 @@ all:
 	-Wconversion -Wsign-conversion \
 	-Wshadow -Wstrict-prototypes \
 	-Wmissing-prototypes -Wformat=2
-
-disasm:
-	gcc -g disasm.c \
-	-Wall -Wextra -Wpedantic \
-	-Wconversion -Wsign-conversion \
-	-Wshadow -Wstrict-prototypes \
-	-Wmissing-prototypes -Wformat=2
diff --git a/disasm.c b/disasm.c
@@ -236,6 +236,31 @@ static void disasm_utype_auipc(uint32_t inst) {
 	printf("auipc x%" PRIu8 ", 0x%05" PRIx32 "\n", u.rd, u.imm);
 }
 
+static void
+disasm_itype_control(uint32_t inst)
+{
+	itype_t i;
+	decode_itype(&i, inst);
+
+	if (i.funct3 != 0x0) {
+		puts("Illegal instruction");
+		return;
+	}
+
+	if (i.imm == 0x0) {
+		puts("ecall");
+		return;
+	} else if (i.imm == 0x1) {
+		puts("ebreak");
+		return;
+	} else {
+		puts("Illegal instruction");
+		return;
+
+	}
+
+}
+
 typedef void (*disasm_fn)(uint32_t inst);
 
 static disasm_fn opcode_table[128];
@@ -247,6 +272,7 @@ init_opcode_table(void)
         opcode_table[0x13] = disasm_itype;
         opcode_table[0x03] = disasm_itype_loads;
         opcode_table[0x67] = disasm_itype_jalr;
+        opcode_table[0x73] = disasm_itype_control;
         opcode_table[0x23] = disasm_stype;
         opcode_table[0x63] = disasm_btype;
         opcode_table[0x6f] = disasm_jtype;
diff --git a/main.c b/main.c
@@ -434,15 +434,40 @@ exec_utype_auipc(cpu_state_t *cpu, uint32_t inst, uint8_t *mem) {
 }
 
 static void
+exec_itype_control(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;
+	}
+
+	if (i.imm == 0x0) {
+		raise_trap(cpu, TRAP_ECALL, inst);
+		return;
+	} else if (i.imm == 0x1) {
+		raise_trap(cpu, TRAP_EBREAK, inst);
+		return;
+	} else {
+		raise_trap(cpu, TRAP_ILLEGAL_INSTRUCTION, inst);
+		return;
+	}
+
+}
+
+static void
 load_program(uint8_t *mem)
 {
 	/* PROGRAM */
 	uint32_t arr[] = {
-		0x00500193,  // addi x3, x0, 5
-		0x00600093,  // addi x1, x0, 6
-		0xaaaaa3b7,  // lui x7, 0xaaaaa		-> rd:aaaaa000
-		//0xfe728ae3   // beq x5, x7, -12 	-> addr 0
-		0x1397	     // auipc x7 0x1 		-> rd 1008
+		0x00500193,	// addi x3, x0, 5
+		0x00600093,	// addi x1, x0, 6
+		0xaaaaa3b7,	// lui x7, 0xaaaaa		-> rd:aaaaa000
+		0x00001397,	// auipc x7 0x1 		-> rd 1008
+		0x00100073,	// ebreak
 	};
 	size_t len = sizeof(arr) / sizeof(arr[0]);
 
@@ -482,6 +507,7 @@ init_opcode_table(void)
         opcode_table[0x13] = exec_itype;
         opcode_table[0x03] = exec_itype_loads;
         opcode_table[0x67] = exec_itype_jalr;
+        opcode_table[0x73] = exec_itype_control;
         opcode_table[0x23] = exec_stype;
         opcode_table[0x63] = exec_btype;
         opcode_table[0x6f] = exec_jtype;
@@ -525,10 +551,12 @@ int main() {
 				raise_trap(&cpu, TRAP_ILLEGAL_INSTRUCTION, inst);
 			}
 
+			fn(&cpu,inst,mem);
+
 			if (cpu.status == CPU_TRAPPED) {
 				printf("CPU trapped\n");
 				switch(cpu.trap.cause) {
-				case TRAP_BREAKPOINT:
+				case TRAP_EBREAK:
 					printf("Code reached breakpoint\n");
 					break;
 				case TRAP_ECALL:
@@ -551,7 +579,6 @@ int main() {
 				return EXIT_FAILURE;
 			}
 
-			fn(&cpu,inst,mem);
 
 		} else if (strncmp(line, "r", 1) == 0 ||
 			   strncmp(line, "registers", 9) == 0) {
diff --git a/trap.h b/trap.h
@@ -3,7 +3,7 @@
 
 typedef enum {
 	TRAP_NONE = 0,
-	TRAP_BREAKPOINT,
+	TRAP_EBREAK,
 	TRAP_ECALL,
 	TRAP_ILLEGAL_INSTRUCTION,
 	TRAP_INSTRUCTION_MISALIGNED,