PCI and ACPI - when resetting all devices, also reset (ie. zero) all of the emulated RAM as well, fixes Windows 2000 after soft reset on later machines such as the ASUS P2B-LS.

src/acpi.c

@@ -1025,8 +1025,10 @@ acpi_reg_write_common_regs(UNUSED(int size), uint16_t addr, uint8_t val, void *p
                         nvr_reg_write(0x000f, 0xff, dev->nvr);
                     }
 
-                    if (sus_typ & SUS_RESET_PCI)
+                    if (sus_typ & SUS_RESET_PCI) {
                         device_reset_all(DEVICE_PCI);
+                        mem_zero();
+                    }
 
                     if (sus_typ & SUS_RESET_CPU)
                         cpu_alt_reset = 0;

src/include/86box/mem.h

@@ -459,6 +459,7 @@ extern void mem_a20_recalc(void);
 
 extern void mem_init(void);
 extern void mem_close(void);
+extern void mem_zero(void);
 extern void mem_reset(void);
 extern void mem_remap_top_ex(int kb, uint32_t start);
 extern void mem_remap_top_ex_nomid(int kb, uint32_t start);

src/mem/mem.c

@@ -2792,6 +2792,17 @@ mem_init_ram_mapping(mem_mapping_t *mapping, uint32_t base, uint32_t size)
     mem_add_ram_mapping(mapping, base, size);
 }
 
+void
+mem_zero(void)
+{
+#if (!(defined __amd64__ || defined _M_X64 || defined __aarch64__ || defined _M_ARM64))
+    if (mem_size > 1048576)
+        memset(ram2, 0x00, ram2_size + 16);
+#endif
+
+    memset(ram, 0x00, ram_size + 16);
+}
+
 /* Reset the memory state. */
 void
 mem_reset(void)
@@ -2867,8 +2878,10 @@ mem_reset(void)
             return;
         }
         memset(ram, 0x00, ram_size + 16);
+#if (!(defined __amd64__ || defined _M_X64 || defined __aarch64__ || defined _M_ARM64))
         if (mem_size > 1048576)
             ram2 = &(ram[1 << 30]);
+#endif
     }
 
     /*

src/pci.c

@@ -419,6 +419,8 @@ pci_trc_reset(uint8_t val)
         mem_a20_recalc();
 
         flushmmucache();
+
+        mem_zero();
     }
 
 #ifdef USE_DYNAREC