From 8bf15f535b82a8c3f1898085ff56b641e8502c61 Mon Sep 17 00:00:00 2001
From: OBattler <oubattler@gmail.com>
Date: Sun, 21 Jun 2020 04:03:14 +0200
Subject: [PATCH] Pages above the top of RAM now have mem[] pointing to a
 4096-byte array of FF's, and fixed the naming and indentation of the P5MP3 in
 machine/machine_table.c.

---
 src/machine/machine_table.c |  2 +-
 src/mem/mem.c               | 36 ++++++++++++++++++++++++++++++------
 2 files changed, 31 insertions(+), 7 deletions(-)

diff --git a/src/machine/machine_table.c b/src/machine/machine_table.c
index 2f8efaba4..4316dfabe 100644
--- a/src/machine/machine_table.c
+++ b/src/machine/machine_table.c
@@ -235,7 +235,7 @@ const machine_t machines[] = {
     { "[i430LX] IBM PS/ValuePoint P60",		"valuepointp60",	MACHINE_TYPE_SOCKET4,		{{"Intel", cpus_Pentium5V},   {"",    NULL},         {"",      NULL},        {"",      NULL},     {"",      NULL}}, MACHINE_PCI | MACHINE_ISA | MACHINE_AT | MACHINE_PS2 | MACHINE_HDC,			 		  2,  128,   2, 127,	machine_at_valuepointp60_init, NULL			},
 #endif
     { "[i430LX] Intel Premiere/PCI",		"revenge",		MACHINE_TYPE_SOCKET4,		{{"Intel", cpus_Pentium5V},   {"",    NULL},         {"",      NULL},        {"",      NULL},     {"",      NULL}}, MACHINE_PCI | MACHINE_ISA | MACHINE_AT | MACHINE_PS2 | MACHINE_HDC,					  2,  128,   2, 127,	       machine_at_batman_init, NULL			},
-    { "[i430LX] ASUS P5MP3",		"p5mp3",		MACHINE_TYPE_SOCKET4,		{{"Intel", cpus_Pentium5V},   {"",    NULL},         {"",      NULL},        {"",      NULL},     {"",      NULL}}, MACHINE_PCI | MACHINE_ISA | MACHINE_AT | MACHINE_PS2 | MACHINE_HDC,			 		  2,  192,   2, 127,	       machine_at_p5mp3_init, NULL			},
+    { "[i430LX] ASUS P/I-P5MP3",		"p5mp3",		MACHINE_TYPE_SOCKET4,		{{"Intel", cpus_Pentium5V},   {"",    NULL},         {"",      NULL},        {"",      NULL},     {"",      NULL}}, MACHINE_PCI | MACHINE_ISA | MACHINE_AT | MACHINE_PS2 | MACHINE_HDC,			 		  2,  192,   2, 127,	        machine_at_p5mp3_init, NULL			},
     { "[i430LX] Micro Star 586MC1",		"586mc1",		MACHINE_TYPE_SOCKET4,		{{"Intel", cpus_Pentium5V},   {"",    NULL},         {"",      NULL},        {"",      NULL},     {"",      NULL}}, MACHINE_PCI | MACHINE_ISA | MACHINE_AT | MACHINE_PS2 | MACHINE_HDC,			 		  2,  128,   2, 127,	       machine_at_586mc1_init, NULL			},
 
     /* Socket 5 machines */
diff --git a/src/mem/mem.c b/src/mem/mem.c
index 5ad097631..572c5878a 100644
--- a/src/mem/mem.c
+++ b/src/mem/mem.c
@@ -81,6 +81,7 @@ page_t			*pages,			/* RAM page table */
 uint32_t		pages_sz;		/* #pages in table */
 
 uint8_t			*ram, *ram2;		/* the virtual RAM */
+uint8_t			page_ff[4096];
 uint32_t		rammask;
 
 uint8_t			*rom;			/* the virtual ROM */
@@ -1720,6 +1721,9 @@ page_remove_from_evict_list(page_t *p)
 void
 mem_write_ramb_page(uint32_t addr, uint8_t val, page_t *p)
 {
+    if ((p != NULL) && (p->mem == page_ff))
+	return;
+
 #ifdef USE_DYNAREC
     if (val != p->mem[addr & 0xfff] || codegen_in_recompile) {
 #else
@@ -1743,6 +1747,9 @@ mem_write_ramb_page(uint32_t addr, uint8_t val, page_t *p)
 void
 mem_write_ramw_page(uint32_t addr, uint16_t val, page_t *p)
 {
+    if ((p != NULL) && (p->mem == page_ff))
+	return;
+
 #ifdef USE_DYNAREC
     if (val != *(uint16_t *)&p->mem[addr & 0xfff] || codegen_in_recompile) {
 #else
@@ -1776,6 +1783,9 @@ mem_write_ramw_page(uint32_t addr, uint16_t val, page_t *p)
 void
 mem_write_raml_page(uint32_t addr, uint32_t val, page_t *p)
 {
+    if ((p != NULL) && (p->mem == page_ff))
+	return;
+
 #ifdef USE_DYNAREC
     if (val != *(uint32_t *)&p->mem[addr & 0xfff] || codegen_in_recompile) {
 #else
@@ -1805,6 +1815,9 @@ mem_write_raml_page(uint32_t addr, uint32_t val, page_t *p)
 void
 mem_write_ramb_page(uint32_t addr, uint8_t val, page_t *p)
 {
+    if ((p != NULL) && (p->mem == page_ff))
+	return;
+
 #ifdef USE_DYNAREC
     if ((p == NULL) || (p->mem == NULL) || (val != p->mem[addr & 0xfff]) || codegen_in_recompile) {
 #else
@@ -1820,6 +1833,9 @@ mem_write_ramb_page(uint32_t addr, uint8_t val, page_t *p)
 void
 mem_write_ramw_page(uint32_t addr, uint16_t val, page_t *p)
 {
+    if ((p != NULL) && (p->mem == page_ff))
+	return;
+
 #ifdef USE_DYNAREC
     if ((p == NULL) || (p->mem == NULL) || (val != *(uint16_t *)&p->mem[addr & 0xfff]) || codegen_in_recompile) {
 #else
@@ -1837,6 +1853,9 @@ mem_write_ramw_page(uint32_t addr, uint16_t val, page_t *p)
 void
 mem_write_raml_page(uint32_t addr, uint32_t val, page_t *p)
 {
+    if ((p != NULL) && (p->mem == page_ff))
+	return;
+
 #ifdef USE_DYNAREC
     if ((p == NULL) || (p->mem == NULL) || (val != *(uint32_t *)&p->mem[addr & 0xfff]) || codegen_in_recompile) {
 #else
@@ -2606,13 +2625,17 @@ mem_log("MEM: reset: new pages=%08lx, pages_sz=%i\n", pages, pages_sz);
 #endif
 
     for (c = 0; c < pages_sz; c++) {
-        if (mem_size > 1048576) {
-		if ((c << 12) < (1 << 30))
+	if ((c << 12) >= (mem_size << 10))
+		pages[c].mem = page_ff;
+	else {
+	        if (mem_size > 1048576) {
+			if ((c << 12) < (1 << 30))
+				pages[c].mem = &ram[c << 12];
+			else
+				pages[c].mem = &ram2[(c << 12) - (1 << 30)];
+		} else
 			pages[c].mem = &ram[c << 12];
-		else
-			pages[c].mem = &ram2[(c << 12) - (1 << 30)];
-	} else
-		pages[c].mem = &ram[c << 12];
+	}
 	if (c < m) {
 		pages[c].write_b = mem_write_ramb_page;
 		pages[c].write_w = mem_write_ramw_page;
@@ -2745,6 +2768,7 @@ mem_init(void)
 #if FIXME
     memset(ff_array, 0xff, sizeof(ff_array));
 #endif
+    memset(page_ff, 0xff, sizeof(page_ff));
 
     /* Reset the memory state. */
     mem_reset();