From d468feaaf511b29880faa297476ff98a9ef81b32 Mon Sep 17 00:00:00 2001
From: Jiri Gaisler <jiri@gaisler.se>
Date: Sat, 30 Aug 2014 23:47:46 +0200
Subject: [PATCH 12/23] sim/erc32: Use memory_iread() function for instruction
 fetching.

	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  | 24 ++++++++++++++++++++++++
 sim/erc32/interf.c |  5 ++---
 sim/erc32/sis.c    |  8 ++------
 sim/erc32/sis.h    |  2 ++
 4 files changed, 30 insertions(+), 9 deletions(-)

diff --git a/sim/erc32/erc32.c b/sim/erc32/erc32.c
index eac49f7..03b40dc 100644
--- a/sim/erc32/erc32.c
+++ b/sim/erc32/erc32.c
@@ -1566,6 +1566,30 @@ store_bytes (mem, waddr, data, sz, ws)
 /* Memory emulation */
 
 int
+memory_iread(addr, data, ws)
+    uint32          addr;
+    uint32         *data;
+    int32          *ws;
+{
+    uint32          asi;
+    if ((addr >= mem_ramstart) && (addr < (mem_ramstart + mem_ramsz))) {
+        *data = *((uint32 *) & (ramb[addr & mem_rammask & ~3]));
+	*ws = mem_ramr_ws;
+	return (0);
+    } else if (addr < mem_romsz) {
+        *data = *((uint32 *) & (romb[addr & ~3]));
+	*ws = mem_romr_ws;
+	return (0);
+    }
+
+    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;
diff --git a/sim/erc32/interf.c b/sim/erc32/interf.c
index 3a72e7f..981aa11 100644
--- a/sim/erc32/interf.c
+++ b/sim/erc32/interf.c
@@ -94,9 +94,8 @@ 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 523d8aa..e109874 100644
--- a/sim/erc32/sis.c
+++ b/sim/erc32/sis.c
@@ -84,7 +84,7 @@ run_sim(sregs, icount, dis)
     uint64          icount;
     int             dis;
 {
-    int             irq, mexc, deb, asi;
+    int             irq, mexc, deb;
 
     sregs->starttime = get_time();
     init_stdio();
@@ -93,11 +93,7 @@ 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 ef5b149..fb733de 100644
--- a/sim/erc32/sis.h
+++ b/sim/erc32/sis.h
@@ -176,6 +176,7 @@ 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,
@@ -186,6 +187,7 @@ 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