implement memory bounds checking

5 files changed, 15 insertions, 1 deletions

diff --git a/src/emu/cpu.c b/src/emu/cpu.c
index 522e2f2..1ac1517 100644
--- a/src/emu/cpu.c
+++ b/src/emu/cpu.c
@@ -54,6 +54,10 @@ void trap(int num)
 		fprintf(stderr, "trap: unaligned memory access\n");
 		abort();
 		break;
+	case TRP_SEGV:
+		fprintf(stderr, "trap: segmentation fault\n");
+		abort();
+		break;
 	case TRP_DIVBYZERO:
 		fprintf(stderr, "trap: division by zero\n");
 		abort();
diff --git a/src/emu/cpu.h b/src/emu/cpu.h
index 9294d7d..6f2a077 100644
--- a/src/emu/cpu.h
+++ b/src/emu/cpu.h
@@ -9,6 +9,7 @@
 /* cpu traps */
 enum {
 	TRP_UNALIGNED,
+	TRP_SEGV,
 	TRP_DIVBYZERO,
 	TRP_SYSCALL,
 	TRP_ILL,
diff --git a/src/emu/mem.c b/src/emu/mem.c
index cdbf2ae..21caafd 100644
--- a/src/emu/mem.c
+++ b/src/emu/mem.c
@@ -1,16 +1,21 @@
 #include <stdint.h>
 #include <sys/types.h>
 #include <string.h>
+#include <inttypes.h>
 
 #include "cpu.h"
 #include "mem.h"
+#include "log.h"
 
 uint8_t *MEM;
+uint64_t mem_size = 64 * 1024 * 1024;
 
 void store(size_t addr, uint32_t value)
 {
 	if (addr & 0x2)
 		trap(TRP_UNALIGNED);
+	if (addr >= mem_size)
+		trap(TRP_SEGV);
 	memcpy(&MEM[addr], &value, 4);
 }
 
@@ -19,12 +24,15 @@ uint32_t load(size_t addr)
 	uint32_t tmp32;
 	if (addr & 0x2)
 		trap(TRP_UNALIGNED);
+	if (addr >= mem_size)
+		trap(TRP_SEGV);
 	memcpy(&tmp32, &MEM[addr], 4);
 	return tmp32;
 }
 
 void push(uint32_t value)
 {
+	//debug("push(%"PRIu32")", value);
 	GPR[SP] -= 4;
 	store(GPR[SP], value);
 }
@@ -32,6 +40,7 @@ void push(uint32_t value)
 uint32_t pop(void)
 {
 	uint32_t tmp32 = load(GPR[SP]);
+	//debug("pop(%"PRIu32")", tmp32);
 	GPR[SP] += 4;
 	return tmp32;
 }
diff --git a/src/emu/mem.h b/src/emu/mem.h
index 985a838..eea391e 100644
--- a/src/emu/mem.h
+++ b/src/emu/mem.h
@@ -5,6 +5,7 @@
 #include <sys/types.h>
 
 extern uint8_t *MEM;
+extern uint64_t mem_size;
 
 void store(size_t addr, uint32_t value);
 uint32_t load(size_t addr);
diff --git a/src/emu/risci.c b/src/emu/risci.c
index 4f73615..a7c99bf 100644
--- a/src/emu/risci.c
+++ b/src/emu/risci.c
@@ -17,7 +17,6 @@
 #include "opc.h"
 
 bool is_debug = false;
-uint64_t mem_size = 64 * 1024 * 1024;
 uint64_t reg_size = 0;
 
 static