joncampbell123/dosbox-x
1
0
Fork 0
mirror of https://github.com/joncampbell123/dosbox-x.git synced 2025-05-09 03:41:10 +08:00
Code Issues Packages Projects Releases Wiki Activity
dosbox-x/include/mem.h

359 lines
14 KiB
C
Raw Blame History

/*
* Copyright (C) 2002-2021 The DOSBox Team
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License along
* with this program; if not, write to the Free Software Foundation, Inc.,
* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
*/
#ifndef DOSBOX_MEM_H
#define DOSBOX_MEM_H
#include "dosbox.h"
#include "byteorder.h"
#define MEM_PAGESIZE (4096U)
/* HostPt and ConstHostPt is for holding linear addresses within this emulator i.e. a normal pointer.
*
* PhysPt is for 32-bit physical memory addresses within the emulation environment.
* PhysPt64 is for 64-bit physical memory addresses for code and device/memory emulation that supports addresses above 4GB.
* LinearPt is a 32-bit linear memory address from the point of view of the CPU execution context, meaning the linear address
* of the code prior to translation through the page tables to physical addresses.
* RealPt is a 32-bit value that holds segment in the upper 16 bits, offset in the lower 16 bits.
*
* Please do not mix these types up in the code, even if they happen to have the same underlying data types */
typedef uint8_t const * ConstHostPt; /* host (virtual) memory address aka ptr */
typedef uint8_t * HostPt; /* host (virtual) memory address aka ptr */
typedef uint32_t PhysPt; /* guest physical memory pointer */
typedef uint32_t LinearPt; /* guest linear memory address */
typedef uint32_t RealPt; /* guest real-mode memory address (16:16 -> seg:offset) */
typedef uint16_t SegmentVal; /* guest segment value */
typedef uint32_t PageNum; /* page frame number */
typedef uint64_t PhysPt64; /* guest physical memory pointer */
typedef int32_t MemHandle;
extern HostPt MemBase;
extern size_t MemSize;
HostPt GetMemBase(void);
bool MEM_A20_Enabled(void);
void MEM_A20_Enable(bool enabled);
/* Memory management / EMS mapping */
Bitu MEM_FreeTotal(void); //Free 4 kb pages
Bitu MEM_FreeLargest(void); //Largest free 4 kb pages block
Bitu MEM_TotalPages(void); //Total amount of 4 kb pages
Bitu MEM_TotalPagesAt4GB(void); //Total amount of 4 kb pages starting at 4GB
Bitu MEM_ConventionalPages(void);
Bitu MEM_AllocatedPages(MemHandle handle); // amount of allocated pages of handle
MemHandle MEM_AllocatePages(Bitu pages,bool sequence);
MemHandle MEM_AllocatePages_A20_friendly(Bitu pages,bool sequence);
MemHandle MEM_GetNextFreePage(void);
void MEM_ReleasePages(MemHandle handle);
bool MEM_ReAllocatePages(MemHandle & handle,Bitu pages,bool sequence);
MemHandle MEM_NextHandle(MemHandle handle);
MemHandle MEM_NextHandleAt(MemHandle handle,Bitu where);
uint32_t MEM_HardwareAllocate(const char *name,uint32_t sz);
static constexpr bool build_memlimit_32bit(void) {
return sizeof(void*) < 8;
}
/*
The following six functions are used everywhere in the end so these should be changed for
Working on big or little endian machines
*/
static INLINE uint8_t host_readb(ConstHostPt const off) {
return *off;
}
static INLINE void host_writeb(HostPt const off,const uint8_t val) {
*off = val;
}
// use __builtin_bswap* for gcc >= 4.3
#if defined(WORDS_BIGENDIAN) && defined(__GNUC__) && \
(__GNUC__ > 4 || (__GNUC__ == 4 && __GNUC_MINOR__ >= 3))
static INLINE uint16_t host_readw(ConstHostPt off) {
return __builtin_bswap16(*(uint16_t *)off);
}
static INLINE uint32_t host_readd(ConstHostPt off) {
return __builtin_bswap32(*(uint32_t *)off);
}
static INLINE void host_writew(HostPt const off, const uint16_t val) {
*(uint16_t *)off = __builtin_bswap16(val);
}
static INLINE void host_writed(HostPt const off, const uint32_t val) {
*(uint32_t *)off = __builtin_bswap32(val);
}
static INLINE void host_writeq(HostPt const off, const uint64_t val) {
*(uint64_t *)off = __builtin_bswap64(val);
}
#elif !defined(C_UNALIGNED_MEMORY)
/* !defined(C_UNALIGNED_MEMORY) meaning: we're probably being compiled for a processor that doesn't like unaligned WORD access,
on such processors typecasting memory as uint16_t and higher can cause a fault if the
address is not aligned to that datatype when we read/write through it. */
static INLINE uint16_t host_readw(ConstHostPt const off) {
return (uint16_t)host_readb(off) + ((uint16_t)host_readb(off+(uintptr_t)1U) << (uint16_t)8U);
}
static INLINE uint32_t host_readd(ConstHostPt const off) {
return (uint32_t)host_readw(off) + ((uint32_t)host_readw(off+(uintptr_t)2U) << (uint32_t)16U);
}
static INLINE uint64_t host_readq(ConstHostPt const off) {
return (uint64_t)host_readd(off) + ((uint64_t)host_readd(off+(uintptr_t)4U) << (uint64_t)32U);
}
static INLINE void host_writew(HostPt const off,const uint16_t val) {
host_writeb(off, (uint8_t)(val));
host_writeb(off+1U,(uint8_t)(val >> (uint16_t)8U));
}
static INLINE void host_writed(HostPt const off,const uint32_t val) {
host_writew(off, (uint16_t)(val));
host_writew(off+2U,(uint16_t)(val >> (uint32_t)16U));
}
static INLINE void host_writeq(HostPt const off,const uint64_t val) {
host_writed(off, (uint32_t)(val));
host_writed(off+4U,(uint32_t)(val >> (uint64_t)32U));
}
#else
static INLINE uint16_t host_readw(ConstHostPt const off) {
return le16toh((*(const uint16_t *)off)); // BSD endian.h
}
static INLINE uint32_t host_readd(ConstHostPt const off) {
return le32toh((*(const uint32_t *)off)); // BSD endian.h
}
static INLINE uint64_t host_readq(ConstHostPt const off) {
return le64toh((*(const uint64_t *)off)); // BSD endian.h
}
static INLINE void host_writew(HostPt const off,const uint16_t val) {
*(uint16_t *)(off) = htole16(val);
}
static INLINE void host_writed(HostPt const off,const uint32_t val) {
*(uint32_t *)(off) = htole32(val);
}
static INLINE void host_writeq(HostPt const off,const uint64_t val) {
*(uint64_t *)(off) = htole64(val);
}
#endif
static INLINE void var_write(uint8_t * const var, const uint8_t val) {
host_writeb(var, val);
}
static INLINE void var_write(uint16_t * const var, const uint16_t val) {
host_writew((HostPt)var, val);
}
static INLINE void var_write(uint32_t * const var, const uint32_t val) {
host_writed((HostPt)var, val);
}
static INLINE void var_write(uint64_t * const var, const uint64_t val) {
host_writeq((HostPt)var, val);
}
static INLINE uint16_t var_read(uint16_t * var) {
return host_readw((ConstHostPt)var);
}
static INLINE uint32_t var_read(uint32_t * var) {
return host_readd((ConstHostPt)var);
}
/* The Following six functions are slower but they recognize the paged memory system */
uint8_t mem_readb(const LinearPt address);
uint16_t mem_readw(const LinearPt address);
uint32_t mem_readd(const LinearPt address);
void mem_writeb(const LinearPt address,const uint8_t val);
void mem_writew(const LinearPt address,const uint16_t val);
void mem_writed(const LinearPt address,const uint32_t val);
void phys_writes(PhysPt addr, const char* string, Bitu length);
/* WARNING: These will cause a segfault or out of bounds access IF
* addr is beyond the end of memory */
/* 2024/12/22: Looking across the DOSBox-X codebase, these functions
* aren't used TOO often, and where they are used, some
* code has memory range checks anyway. So it doesn't hurt
* performance very much if at all to just put the range
* check here instead, in order not to segfault if somehow
* the address given is beyond end of system memory. --J.C.
*
* There is one more important detail here. These functions
* take only a 32-bit physical address. Which means if more
* than 32 address bits are enabled on the CPU and the OS
* has PSE/PAE page tables enabled, these functions will not
* be able to reach above 4GB. Given how memory will be
* segmented between the 'below 4GB' and 'above 4GB' regions,
* if emulating 4GB or more, that is perfectly fine. S3 XGA
* and ISA DMA emulation will never reach above 4GB anyway.
*
* The way the range check is done is ideal for performance,
* yet may fail to work correctly if MemSize is very close
* to zero, low enough that subtraction would cause it to
* wrap back around to the largest possible value. The code,
* when MemBase is a valid pointer, will never set MemSize
* that small. */
/* NTS: Technically these phys_ functions are misnamed. They don't read/write
* all physically addressable memory and MMIO attached to the CPU. These
* functions can only address system RAM. So perhaps they should be named
* physmem_read/physmem_write instead and a physmmio_read/physmmio_write
* function should be added that addresses the "physical" memory addresses
* accessible to the CPU. That hackery in the debugger to dump by physical
* memory addresse could be a useful guide on how to do that. --J.C. */
static INLINE void phys_writeb(const PhysPt addr,const uint8_t val) {
if (addr < MemSize)
host_writeb(MemBase+addr,val);
}
static INLINE void phys_writew(const PhysPt addr,const uint16_t val) {
if (addr < (MemSize-1u))
host_writew(MemBase+addr,val);
}
static INLINE void phys_writed(const PhysPt addr,const uint32_t val) {
if (addr < (MemSize-3u))
host_writed(MemBase+addr,val);
}
static INLINE uint8_t phys_readb(const PhysPt addr) {
if (addr < MemSize)
return host_readb(MemBase+addr);
else
return 0xFF;
}
static INLINE uint16_t phys_readw(const PhysPt addr) {
if (addr < (MemSize-1u))
return host_readw(MemBase+addr);
else
return 0xFFFFu;
}
static INLINE uint32_t phys_readd(const PhysPt addr) {
if (addr < (MemSize-3u))
return host_readd(MemBase+addr);
else
return 0xFFFFFFFFu;
}
/* These don't check for alignment, better be sure it's correct */
void MEM_BlockWrite(LinearPt pt, const void *data, size_t size);
void MEM_BlockRead(LinearPt pt,void * data,Bitu size);
void MEM_BlockWrite32(LinearPt pt,void * data,Bitu size);
void MEM_BlockRead32(LinearPt pt,void * data,Bitu size);
void MEM_BlockCopy(LinearPt dest,LinearPt src,Bitu size);
void MEM_StrCopy(LinearPt pt,char * data,Bitu size);
void mem_memcpy(LinearPt dest,LinearPt src,Bitu size);
Bitu mem_strlen(LinearPt pt);
void mem_strcpy(LinearPt dest,LinearPt src);
/* The following functions are all shortcuts to the above functions using physical addressing */
static inline constexpr LinearPt PhysMake(const uint16_t seg,const uint16_t off) {
return ((LinearPt)seg << 4U) + (LinearPt)off;
}
static inline constexpr uint16_t RealSeg(const RealPt pt) {
return (uint16_t)(pt >> 16U);
}
static inline constexpr uint16_t RealOff(const RealPt pt) {
return (uint16_t)(pt & 0xffffu);
}
static inline constexpr LinearPt Real2Phys(const RealPt pt) {
return (((LinearPt)RealSeg(pt) << 4U) + (LinearPt)RealOff(pt));
}
static inline constexpr RealPt RealMake(const uint16_t seg,const uint16_t off) {
return (((RealPt)seg << 16U) + (RealPt)off);
}
/* convert physical address to 4:16 real pointer (example: 0xABCDE -> 0xA000:0xBCDE) */
static inline constexpr RealPt PhysToReal416(const LinearPt phys) {
return RealMake((uint16_t)((phys >> 4U) & 0xF000U),(uint16_t)(phys & 0xFFFFU));
}
static inline constexpr LinearPt RealVecAddress(const uint8_t vec) {
return ((unsigned int)vec << 2U);
}
static INLINE uint8_t real_readb(const uint16_t seg,const uint16_t off) {
return mem_readb(PhysMake(seg,off));
}
static INLINE uint16_t real_readw(const uint16_t seg,const uint16_t off) {
return mem_readw(PhysMake(seg,off));
}
static INLINE uint32_t real_readd(const uint16_t seg,const uint16_t off) {
return mem_readd(PhysMake(seg,off));
}
static INLINE void real_writeb(const uint16_t seg,const uint16_t off,const uint8_t val) {
mem_writeb(PhysMake(seg,off),val);
}
static INLINE void real_writew(const uint16_t seg,const uint16_t off,const uint16_t val) {
mem_writew(PhysMake(seg,off),val);
}
static INLINE void real_writed(const uint16_t seg,const uint16_t off,const uint32_t val) {
mem_writed(PhysMake(seg,off),val);
}
static INLINE RealPt RealGetVec(const uint8_t vec) {
return mem_readd(RealVecAddress(vec));
}
static INLINE void RealSetVec(const uint8_t vec,const RealPt pt) {
mem_writed(RealVecAddress(vec),pt);
}
static INLINE void RealSetVec(const uint8_t vec,const RealPt pt,RealPt &old) {
const LinearPt addr = RealVecAddress(vec);
old = mem_readd(addr);
mem_writed(addr,pt);
}
uint8_t physdev_readb(const PhysPt64 addr);
uint16_t physdev_readw(const PhysPt64 addr);
uint32_t physdev_readd(const PhysPt64 addr);
void physdev_writeb(const PhysPt64 addr,const uint8_t val);
void physdev_writew(const PhysPt64 addr,const uint16_t val);
void physdev_writed(const PhysPt64 addr,const uint32_t val);
uint32_t MEM_get_address_bits();
uint32_t MEM_get_address_bits4GB();
void MEM_ResetPageHandler_Unmapped(Bitu phys_page, Bitu pages);
#endif
Reference in New Issue View Git Blame Copy Permalink