[PATCH v4 04/13] sim/erc32: Use memory_iread() function for instruction fetching.

Jiri Gaisler
2015-03-17T21:03:08Z

Use separate memory_iread() function for instruction fetching.
Speeds up execution and allows addition of an MMU at a later stage.

* erc32.c (memory_iread): New function to fetch instructions.
* interf.c (run_sim): Use memory_iread.
* sis.c (run_sim): As above.
---
sim/erc32/erc32.c | 38 ++++++++++++++++++++++++++++++++------
sim/erc32/interf.c | 5 ++---
sim/erc32/sis.c | 8 ++------
sim/erc32/sis.h | 2 ++
4 files changed, 38 insertions(+), 15 deletions(-)

diff --git a/sim/erc32/erc32.c b/sim/erc32/erc32.c
index 8c0ddd3..c6d67ac 100644
--- a/sim/erc32/erc32.c
+++ b/sim/erc32/erc32.c
@@ -1083,7 +1083,7 @@ read_uart(addr)
return tmp;
#endif
#else
- return(0);
+ return 0;
#endif
break;

@@ -1115,7 +1115,7 @@ read_uart(addr)
return tmp;
#endif
#else
- return(0);
+ return 0;
#endif
break;

@@ -1155,7 +1155,7 @@ read_uart(addr)
return (uart_stat_reg);
#endif
#else
- return(0x00060006);
+ return 0x00060006;
#endif
break;
default:
@@ -1565,6 +1565,31 @@ store_bytes (mem, waddr, data, sz, ws)
/* Memory emulation */

int
+memory_iread(uint32 addr, uint32 *data, int32 *ws)
+{
+ uint32 asi;
+ if ((addr >= mem_ramstart) && (addr < (mem_ramstart + mem_ramsz))) {
+ memcpy (data, &ramb[addr & mem_rammask & ~3], 4);
+ *ws = mem_ramr_ws;
+ return (0);
+ } else if (addr < mem_romsz) {
+ memcpy (data, &romb[addr & ~3], 4);
+ *ws = mem_romr_ws;
+ return (0);
+ }
+
+ if (sis_verbose)
+ printf ("Memory exception at %x (illegal address)\n", addr);
+ if (sregs.psr & 0x080)
+ asi = 9;
+ else
+ asi = 8;
+ set_sfsr (UIMP_ACC, addr, asi, 1);
+ *ws = MEM_EX_WS;
+ return 1;
+}
+
+int
memory_read(asi, addr, data, sz, ws)
int32 asi;
uint32 addr;
@@ -1582,7 +1607,7 @@ memory_read(asi, addr, data, sz, ws)
if (errmec == 5) mecparerror();
if (errmec == 6) iucomperr();
errmec = 0;
- return(1);
+ return 1;
}
#endif

@@ -1631,7 +1656,8 @@ memory_read(asi, addr, data, sz, ws)

}

- printf("Memory exception at %x (illegal address)\n", addr);
+ if (sis_verbose)
+ printf ("Memory exception at %x (illegal address)\n", addr);
set_sfsr(UIMP_ACC, addr, asi, 1);
*ws = MEM_EX_WS;
return (1);
@@ -1661,7 +1687,7 @@ memory_write(asi, addr, data, sz, ws)
if (errmec == 5) mecparerror();
if (errmec == 6) iucomperr();
errmec = 0;
- return(1);
+ return 1;
}
#endif

diff --git a/sim/erc32/interf.c b/sim/erc32/interf.c
index 97540a9..098b9ce 100644
--- a/sim/erc32/interf.c
+++ b/sim/erc32/interf.c
@@ -96,9 +96,8 @@ run_sim(sregs, icount, dis)
if (sregs->pc == 0 || sregs->npc == 0)
printf ("bogus pc or npc\n");
#endif
- mexc = memory_read(sregs->asi, sregs->pc, &sregs->inst,
- 2, &sregs->hold);
-#if 1 /* DELETE ME! for debugging purposes only */
+ mexc = memory_iread (sregs->pc, &sregs->inst, &sregs->hold);
+#if 0 /* DELETE ME! for debugging purposes only */
if (sis_verbose > 2)
printf("pc %x, np %x, sp %x, fp %x, wm %x, cw %x, i %08x\n",
sregs->pc, sregs->npc,
diff --git a/sim/erc32/sis.c b/sim/erc32/sis.c
index dcb5ebf..b066a56 100644
--- a/sim/erc32/sis.c
+++ b/sim/erc32/sis.c
@@ -75,7 +75,7 @@ run_sim(sregs, icount, dis)
uint64 icount;
int dis;
{
- int irq, mexc, deb, asi;
+ int irq, mexc, deb;

sregs->starttime = get_time();
init_stdio();
@@ -84,11 +84,7 @@ run_sim(sregs, icount, dis)
irq = 0;
while (icount > 0) {

- if (sregs->psr & 0x080)
- asi = 9;
- else
- asi = 8;
- mexc = memory_read(asi, sregs->pc, &sregs->inst, 2, &sregs->hold);
+ mexc = memory_iread(sregs->pc, &sregs->inst, &sregs->hold);
sregs->icnt = 1;
if (sregs->annul) {
sregs->annul = 0;
diff --git a/sim/erc32/sis.h b/sim/erc32/sis.h
index 74466ae..d21bf49 100644
--- a/sim/erc32/sis.h
+++ b/sim/erc32/sis.h
@@ -169,6 +169,7 @@ extern void sim_halt (void);
extern void exit_sim (void);
extern void init_stdio (void);
extern void restore_stdio (void);
+extern int memory_iread (uint32 addr, uint32 *data, int32 *ws);
extern int memory_read (int32 asi, uint32 addr, uint32 *data,
int32 sz, int32 *ws);
extern int memory_write (int32 asi, uint32 addr, uint32 *data,
@@ -179,6 +180,7 @@ extern int sis_memory_read (uint32 addr, char *data,
uint32 length);

/* func.c */
+extern struct pstate sregs;
extern void set_regi (struct pstate *sregs, int32 reg,
uint32 rval);
extern void get_regi (struct pstate *sregs, int32 reg, char *buf);
--
1.9.1