riscv

commit 77c753a76dc481afb44b3b8596ac00f4cf4e5a63
parent 3960a8a7fe04cce7b2ce8657f7fe410a913ec6ec
Author: Brian Swetland <swetland@frotz.net>
Date:   Wed, 23 Oct 2019 08:46:22 -0700

rvsim: custom ops

- wire up _exit, _exiti, _putc custom ops
- disable debug tracing

Diffstat:
M
Makefile
 | 
2
+-
M
rvmain.c
 | 
5
+++++
M
rvsim.c
 | 
27
+++++++++++++++++++++------
M
rvsim.h
 | 
2
+-

4 files changed, 28 insertions(+), 8 deletions(-)
diff --git a/Makefile b/Makefile
@@ -22,7 +22,7 @@ out/%.lst: out/%.elf
 HELLO_SRCS := start.S hello.c
 out/hello.elf: $(HELLO_SRCS) Makefile
 	@mkdir -p out
-	$(CC) $(CFLAGS) -o $@ $(HELLO_SRCS)
+	$(CC) $(CFLAGS) -o $@ $(HELLO_SRCS) -lgcc
 
 RVSIM_SRCS := rvmain.c rvsim.c rvdis.c
 bin/rvsim: $(RVSIM_SRCS) Makefile gen/instab.h
diff --git a/rvmain.c b/rvmain.c
@@ -18,6 +18,11 @@ uint32_t ior32(uint32_t addr) {
 void iow32(uint32_t addr, uint32_t val) {
 }
 
+void ioputc(uint32_t c) {
+	uint8_t x = c;
+	if (write(1, &x, 1)) {} // appease warning
+}
+
 int load_image(const char* fn, uint8_t* ptr, size_t sz) {
 	struct stat s;
 	int fd = open(fn, O_RDONLY);
diff --git a/rvsim.c b/rvsim.c
@@ -9,10 +9,10 @@
 #include "riscv.h"
 #include "rvsim.h"
 
-#define DO_TRACE_INS     1
-#define DO_TRACE_TRAPS   1
-#define DO_TRACE_MEM_WR  1
-#define DO_TRACE_REG_WR  1
+#define DO_TRACE_INS     0
+#define DO_TRACE_TRAPS   0
+#define DO_TRACE_MEM_WR  0
+#define DO_TRACE_REG_WR  0
 
 #define RVMEMBASE 0x80000000
 #define RVMEMSIZE 32768
@@ -149,14 +149,16 @@ static uint32_t get_csr(rvstate_t* s, uint32_t csr) {
 	fprintf(stderr, "          ([%08x] = %08x)\n", a, v);\
 	} while (0)
 #else
-#define trace_mem_wr(v) do {} while (0)
+#define trace_mem_wr(a, v) do {} while (0)
 #endif
 
 int rvsim_exec(rvstate_t* s, uint32_t _pc) {
 	uint32_t pc = _pc;
 	uint32_t next = _pc;
 	uint32_t ins;
+	uint64_t ccount = 0;
 	for (;;) {
+		ccount++;
 		pc = next;
 		ins = rd32(s->memory, pc);
 #if DO_TRACE_INS
@@ -197,7 +199,20 @@ int rvsim_exec(rvstate_t* s, uint32_t _pc) {
 			goto trap_common;
 		}
 		case OC_CUSTOM_0:
-			return 0;
+			switch (get_fn3(ins)) {
+			case 0b000: // _exiti
+				fprintf(stderr, "CCOUNT %lu\n", ccount);
+				return get_ii(ins);
+			case 0b100: // _exit
+				fprintf(stderr, "CCOUNT %lu\n", ccount);
+				return RdR1();
+			case 0b101: // _putc
+				ioputc(RdR1());
+				break;
+			default:
+				goto inval;
+			}
+			break;
 		case OC_MISC_MEM:
 			switch (get_fn3(ins)) {
 			case F3_FENCE:
diff --git a/rvsim.h b/rvsim.h
@@ -13,5 +13,5 @@ uint32_t rvsim_rd32(rvstate_t* s, uint32_t addr);
 
 uint32_t ior32(uint32_t addr);
 void iow32(uint32_t addr, uint32_t val);
-
+void ioputc(uint32_t c);