Begin adding ACPI emulation. Start with an independent memory region …

…at top of 4GB RAM where the tables will go. The general design of DOSBox-X does not allow just taking from top of RAM like some BIOSes do

include/bios.h

@@ -325,6 +325,17 @@ class ISAPnPDevice {
     size_t              alloc_sz = 0;
 };
 
+extern bool ACPI_enabled;
+extern uint32_t ACPI_BASE;
+extern uint32_t ACPI_REGION_SIZE; // power of 2
+extern uint32_t ACPI_version;
+extern unsigned char *ACPI_buffer;
+extern size_t ACPI_buffer_size;
+
+void ACPI_mem_enable(const bool enable);
+void ACPI_free();
+bool ACPI_init();
+
 /* abc = ASCII letters of the alphabet
  * defg = hexadecimal digits */
 #define ISAPNP_ID(a,b,c,d,e,f,g) \

src/hardware/memory.cpp

@@ -45,6 +45,103 @@
 #include "../gamelink/gamelink.h"
 #endif // C_GAMELINK
 
+// ACPI memory region allocation.
+// Most ACPI BIOSes actually use some region at top of memory, but the
+// design of DOSBox-X doesn't make that possible, so the ACPI tables are
+// written to a high memory region just below the top 4GB region and the
+// RSD PTR in the legacy BIOS region (0xE0000-0xFFFFF) will point at that.
+// A memory address is chosen, which must be maintained once tables are
+// generated because tables point at each other by physical memory address.
+// A fixed size region is chosen within which the tables are written.
+//
+// NTS: ACPI didn't happen until the Pentium era when it became quite rare
+//      for CPUs to have less than 32 address bits. No 26-bit 486SX limits
+//      here. For this reason, ACPI is not supported unless all 32 address
+//      bits are enabled.
+bool ACPI_enabled = false;
+bool acpi_mem_setup = false;
+uint32_t ACPI_BASE=0;
+uint32_t ACPI_REGION_SIZE=0; // power of 2
+uint32_t ACPI_version=0;
+unsigned char *ACPI_buffer=NULL;
+size_t ACPI_buffer_size=0;
+
+class ACPIPageHandler : public PageHandler {
+	public:
+		ACPIPageHandler() : PageHandler(PFLAG_NOCODE) {}
+		ACPIPageHandler(Bitu flags) : PageHandler(flags) {}
+		uint8_t readb(PhysPt addr) {
+			if (ACPI_buffer != NULL) {
+				const PhysPt rel = addr - ACPI_BASE;
+				if (rel < ACPI_buffer_size) return ACPI_buffer[rel];
+			}
+
+			return 0xFF;
+		}
+		void writeb(PhysPt addr,uint8_t val){
+			LOG(LOG_CPU,LOG_ERROR)("Write %x to acpi at %x",(int)val,(int)addr);
+		}
+		void writew(PhysPt addr,uint16_t val){
+			LOG(LOG_CPU,LOG_ERROR)("Write %x to acpi at %x",(int)val,(int)addr);
+		}
+		void writed(PhysPt addr,uint32_t val){
+			LOG(LOG_CPU,LOG_ERROR)("Write %x to acpi at %x",(int)val,(int)addr);
+		}
+};
+
+static ACPIPageHandler acpi_mem_handler;
+
+PageHandler* acpi_memio_cb(MEM_CalloutObject &co,Bitu phys_page) {
+	(void)co;//UNUSED
+	(void)phys_page;//UNUSED
+
+	if (ACPI_buffer != NULL && ACPI_REGION_SIZE != 0 && phys_page >= (ACPI_BASE/4096) && phys_page < ((ACPI_BASE+ACPI_REGION_SIZE)/4096))
+		return &acpi_mem_handler;
+
+	return NULL;
+}
+
+void MEM_ResetPageHandler_Unmapped(Bitu phys_page, Bitu pages);
+
+void ACPI_mem_enable(const bool enable) {
+	if (enable && !acpi_mem_setup) {
+		if (ACPI_BASE != 0 && ACPI_REGION_SIZE != 0) {
+			MEM_SetPageHandler( ACPI_BASE/4096, ACPI_REGION_SIZE/4096, &acpi_mem_handler );
+			acpi_mem_setup = true;
+			PAGING_ClearTLB();
+		}
+	}
+	else if (!enable && acpi_mem_setup) {
+		if (ACPI_BASE != 0 && ACPI_REGION_SIZE != 0) {
+			MEM_ResetPageHandler_Unmapped( ACPI_BASE/4096, ACPI_REGION_SIZE/4096 );
+			acpi_mem_setup = false;
+			PAGING_ClearTLB();
+		}
+	}
+}
+
+void ACPI_free() {
+	if (ACPI_buffer != NULL) {
+		delete[] ACPI_buffer;
+		ACPI_buffer = NULL;
+	}
+	ACPI_buffer_size = 0;
+}
+
+bool ACPI_init() {
+	if (ACPI_buffer == NULL) {
+		if (ACPI_REGION_SIZE == 0 || ACPI_REGION_SIZE > (8ul << 20ull))
+			return false;
+
+		ACPI_buffer_size = ACPI_REGION_SIZE;
+		ACPI_buffer = new unsigned char [ACPI_buffer_size];
+		if (ACPI_buffer == NULL)
+			return false;
+	}
+
+	return (ACPI_buffer != NULL);
+}
+
 static MEM_Callout_t lfb_mem_cb = MEM_Callout_t_none;
 static MEM_Callout_t lfb_mmio_cb = MEM_Callout_t_none;
 
@@ -156,7 +253,7 @@ class IllegalPageHandler : public PageHandler {
 
 class RAMPageHandler : public PageHandler {
 public:
-    RAMPageHandler() : PageHandler(PFLAG_READABLE|PFLAG_WRITEABLE) {}
+    RAMPageHandler() : PageHandler(PFLAG_READABLE|PFLAG_WRITEABLE|PFLAG_NOCODE) {}
     RAMPageHandler(Bitu flags) : PageHandler(flags) {}
     HostPt GetHostReadPt(Bitu phys_page) {
         if (!a20_fast_changeable || (phys_page & (~0xFul/*64KB*/)) == 0x100ul/*@1MB*/)
@@ -1770,6 +1867,7 @@ void ShutDownRAM(Section * sec) {
 #endif
         MemBase = NULL;
     }
+    ACPI_free();
 }
 
 void MEM_InitCallouts(void) {

src/ints/bios.cpp

@@ -7970,24 +7970,51 @@ class BIOS:public Module_base{
 # endif
 #endif
 
+	ACPI_mem_enable(false);
+	ACPI_REGION_SIZE = 0;
+	ACPI_BASE = 0;
+	ACPI_enabled = false;
+	ACPI_version = 0;
+	ACPI_free();
+
         /* If we're here because of a JMP to F000:FFF0 from a DOS program, then
          * an actual reset is needed to prevent reentrancy problems with the DOS
          * kernel shell. The WINNT.EXE install program for Windows NT/2000/XP
          * likes to restart the program by JMPing to F000:FFF0 */
         if (!dos_kernel_disabled && first_shell != NULL) {
 		LOG(LOG_MISC,LOG_DEBUG)("BIOS POST: JMP to F000:FFF0 detected, initiating proper reset");
 		throw int(9);
-        }
-
-        {
-            Section_prop * section=static_cast<Section_prop *>(control->GetSection("dosbox"));
-            int val = section->Get_int("reboot delay");
-
-            if (val < 0)
-                val = IS_PC98_ARCH ? 1000 : 500;
+	}
 
-            reset_post_delay = (unsigned int)val;
-        }
+	{
+		Section_prop * section=static_cast<Section_prop *>(control->GetSection("dosbox"));
+		int val = section->Get_int("reboot delay");
+
+		if (val < 0)
+			val = IS_PC98_ARCH ? 1000 : 500;
+
+		reset_post_delay = (unsigned int)val;
+
+		/* Read the ACPI setting and decide on a ACPI region to use */
+		{
+			std::string s = section->Get_string("acpi");
+
+			if (IS_PC98_ARCH) {
+				/* do not enable ACPI, PC-98 does not have it */
+			}
+			else if (MEM_get_address_bits() < 32) {
+				/* I doubt any 486DX systems with less than 32 address bits has ACPI */
+			}
+			else if (s == "1.0") {
+				ACPI_version = 0x100;
+				ACPI_REGION_SIZE = (256u << 10u); // 256KB
+			}
+			else if (s == "1.0b") {
+				ACPI_version = 0x10B;
+				ACPI_REGION_SIZE = (256u << 10u); // 256KB
+			}
+		}
+	}
 
         if (bios_post_counter != 0 && reset_post_delay != 0) {
             /* reboot delay, in case the guest OS/application had something to day before hitting the "reset" signal */
@@ -8261,6 +8288,19 @@ class BIOS:public Module_base{
         bios_has_exec_vga_bios = false;
         LOG(LOG_MISC,LOG_DEBUG)("BIOS: executing POST routine");
 
+	if (ACPI_REGION_SIZE != 0) {
+		// place it just below the mirror of the BIOS at FFFF0000
+		ACPI_BASE = 0xFFFF0000 - ACPI_REGION_SIZE;
+
+		LOG(LOG_MISC,LOG_DEBUG)("ACPI: Setting up version %u.%02x at 0x%lx-0x%lx",
+				ACPI_version>>8,ACPI_version&0xFF,
+				(unsigned long)ACPI_BASE,(unsigned long)(ACPI_BASE+ACPI_REGION_SIZE-1lu));
+
+		ACPI_init();
+		ACPI_mem_enable(true);
+		memset(ACPI_buffer,0,ACPI_buffer_size);
+	}
+
         // TODO: Anything we can test in the CPU here?
 
         // initialize registers