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core: stdint typedefs, LE optimizations, frame determinism

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Three follow-up audit passes on top of the memory-safety / leak /
savestate-portability work in 1185db8.

==============================================================
Pass 1: replace custom typedefs with C99 stdint types throughout
==============================================================

The custom uint8 / uint16 / uint32 / uint64 / int8 / int16 / int32 /
int64 typedefs in src/fceu-types.h were just simple aliases for the
C99 stdint.h types. Replace them with the standard names directly.

  - 498 files modified
  - ~3,400 token replacements (uint8 -> uint8_t, etc)
  - fceu-types.h slimmed down to just INLINE / GINLINE / FASTAPASS
    macros and the readfunc / writefunc function-pointer typedefs
    (those now use uint8_t / uint32_t natively)
  - Build clean on `make platform=unix` with zero new warnings
  - Output binary size unchanged - confirming semantic equivalence

Mechanical replacement done with a Python script that uses word-
boundary regex to avoid false positives (e.g. 'uint32_t' was
correctly left alone because '_' is a word character so 'uint32'
is not a complete word inside it).

================================================================
Pass 2: prefer memcpy on LE hosts for endian read/write helpers
================================================================

fceu-endian.c's write32le_mem, FCEU_en32lsb, and FCEU_de32lsb
performed bytewise composition/decomposition unconditionally. On
LE hosts the in-memory representation already matches the desired
LE on-disk format, so a single memcpy is equivalent and lets the
compiler emit a single load/store rather than four byte ops.

  - The bytewise path is kept inside #ifdef MSB_FIRST for BE hosts
    where it implements the actual byte swap
  - Both forms produce identical results; this is a code-clarity
    change more than a performance one (the optimizer was already
    merging the shifts on LE), but it documents the intent and
    removes a strict-aliasing-flavoured cast through
    *(uint32_t*)Bufo
  - Added missing #include <string.h> in fceu-endian.c which was
    relying on transitive includes for memcpy

Other MSB_FIRST sites in the codebase (state.c FlipByteOrder
guards, ppu.c sprite-line rendering, boards/unrom512.c flash-write-
counter access) were already optimized for LE; they were verified
correct rather than changed.

================================================================
Pass 3: frame determinism for replay and netplay
================================================================

Two libc rand() sites in core were replaced with a local xorshift32
PRNG so that NES games which read uninitialised memory or hit
hardware "weak bit" emulation produce reproducible behaviour across
runs. NES titles routinely read uninitialised RAM (variables not
zeroed before use, sprite Y-position set by junk-on-stack), so the
RAM contents at power-on subtly affect game behaviour. With libc
rand(), those contents depend on whether anyone else seeded rand()
in the same process - a different libretro frontend, a different
audio backend init order, or any frontend that does srand(time(0))
all break replay / netplay frame-determinism.

1. fceu.c FCEU_MemoryRand. Used to fill RAM (PowerNES) and CHR-RAM
   (iNES_Init) at power-on when option_ramstate=2 (random init).
   Replaced with a local xorshift32 PRNG, exposed via a new
   FCEU_MemoryRand_Reseed(uint32_t) function called once per
   power-on:
   - PowerNES seeds from the first 4 bytes of GameInfo->MD5 (set
     by all loaders before PowerNES runs) so identical ROMs
     produce identical RAM, different ROMs differ
   - iNES_Init seeds from iNESCart.PRGCRC32 before the CHR-RAM
     fill so two builds of the same ROM get the same CHR-RAM
   - The PRNG state advances across multiple FCEU_MemoryRand
     calls within one power-on so RAM and CHR-RAM get different
     content (matching NES hardware reality)

2. boards/rt-01.c UNLRT01Read. The RT-01 board has 'weak bit'
   protected EPROM regions; reads of 0xCE80-0xCEFF and 0xFE80-
   0xFEFF return 0xF2 with the low 3 bits randomised. Replaced
   libc rand() with a local xorshift32 seeded at power-on, and
   added the PRNG state to the savestate via AddExState with key
   "WBKS" so save / load / rewind / netplay rollback all stay
   deterministic.

In addition, two long-double-to-int truncations were changed to
double for cross-platform FP determinism:

  - sound.c SetSoundVariables: soundtsinc
  - boards/n106.c DoNamcoSound: inc

long double has platform-dependent precision (80-bit on x87,
64-bit with -mfpmath=sse, 128-bit on PowerPC), so the truncated
integer result varied across these platforms. double is
guaranteed 64-bit IEEE-754 portably.

After this pass, the core has no time(), clock(), gettimeofday(),
clock_gettime(), getpid(), getuid(), getgid(), getenv(), gethostid(),
pthread, std::thread, OpenMP, signal handler, or non-deterministic-
malloc dependency. Verified with a Python scanner that greps the
source for these patterns; runs clean.

The PPU / APU / CPU power-on already explicitly memset all state
buffers to 0 (deterministic), and ROM/CHR-ROM allocation already
memsets to 0xFF before partial fread (deterministic regardless of
file truncation).

Combined with the memory-safety hardening in 1185db8 (which
prevents savestate-loaded indices from going out-of-bounds and
producing unpredictable behaviour), the core now offers genuine
frame-deterministic replay across runs, builds, and host endian.
This commit is contained in:
U-DESKTOP-SPFP6AQ\twistedtechre
2026-05-04 02:46:34 +02:00
parent 1185db89c1
commit 766f84662b
499 changed files with 3507 additions and 3416 deletions
Download Patch File Download Diff File Expand all files Collapse all files

80
src/fds.c
View File

@@ -56,29 +56,29 @@ static void FDSClose(void);
static void FP_FASTAPASS(1) FDSFix(int a);
static uint8 FDSRegs[6];
static int32 IRQLatch, IRQCount;
static uint8 IRQa;
static uint8_t FDSRegs[6];
static int32_t IRQLatch, IRQCount;
static uint8_t IRQa;
static uint8 *FDSROM = NULL;
static uint32 FDSROMSize = 0;
static uint8 *FDSRAM = NULL;
static uint32 FDSRAMSize;
static uint8 *FDSBIOS = NULL;
static uint32 FDSBIOSsize;
static uint8 *CHRRAM = NULL;
static uint32 CHRRAMSize;
static uint8_t *FDSROM = NULL;
static uint32_t FDSROMSize = 0;
static uint8_t *FDSRAM = NULL;
static uint32_t FDSRAMSize;
static uint8_t *FDSBIOS = NULL;
static uint32_t FDSBIOSsize;
static uint8_t *CHRRAM = NULL;
static uint32_t CHRRAMSize;
/* Original disk data backup, to help in creating save states. */
static uint8 *diskdatao[8] = { 0, 0, 0, 0, 0, 0, 0, 0 };
static uint8 *diskdata[8] = { 0, 0, 0, 0, 0, 0, 0, 0 };
static uint8_t *diskdatao[8] = { 0, 0, 0, 0, 0, 0, 0, 0 };
static uint8_t *diskdata[8] = { 0, 0, 0, 0, 0, 0, 0, 0 };
static uint32 TotalSides;
static uint8 DiskWritten = 0; /* Set to 1 if disk was written to. */
static uint8 writeskip;
static int32 DiskPtr;
static int32 DiskSeekIRQ;
static uint8 SelectDisk, InDisk;
static uint32_t TotalSides;
static uint8_t DiskWritten = 0; /* Set to 1 if disk was written to. */
static uint8_t writeskip;
static int32_t DiskPtr;
static int32_t DiskSeekIRQ;
static uint8_t SelectDisk, InDisk;
enum FDS_DiskBlockIDs {
DSK_INIT = 0,
@@ -88,13 +88,13 @@ enum FDS_DiskBlockIDs {
DSK_FILEDATA
};
static uint8 mapperFDS_control; /* 4025(w) control register */
static uint16 mapperFDS_filesize; /* size of file being read/written */
static uint8 mapperFDS_block; /* block-id of current block */
static uint16 mapperFDS_blockstart; /* start-address of current block */
static uint16 mapperFDS_blocklen; /* length of current block */
static uint16 mapperFDS_diskaddr; /* current address relative to blockstart */
static uint8 mapperFDS_diskaccess; /* disk needs to be accessed at least once before writing */
static uint8_t mapperFDS_control; /* 4025(w) control register */
static uint16_t mapperFDS_filesize; /* size of file being read/written */
static uint8_t mapperFDS_block; /* block-id of current block */
static uint16_t mapperFDS_blockstart; /* start-address of current block */
static uint16_t mapperFDS_blocklen; /* length of current block */
static uint16_t mapperFDS_diskaddr; /* current address relative to blockstart */
static uint8_t mapperFDS_diskaccess; /* disk needs to be accessed at least once before writing */
#define GET_FDS_DISK() (diskdata[InDisk][mapperFDS_blockstart + mapperFDS_diskaddr])
#define FDS_DISK_INSERTED (InDisk != 255)
@@ -102,11 +102,11 @@ static uint8 mapperFDS_diskaccess; /* disk needs to be accessed at least once b
#define DC_INC 1
#define BYTES_PER_SIDE 65500
uint8 *FDSROM_ptr(void) {
uint8_t *FDSROM_ptr(void) {
return (FDSROM);
}
uint32 FDSROM_size(void) {
uint32_t FDSROM_size(void) {
return (FDSROMSize);
}
@@ -249,7 +249,7 @@ static void FP_FASTAPASS(1) FDSFix(int a) {
}
static DECLFR(FDSRead4030) {
uint8 ret = 0;
uint8_t ret = 0;
/* Cheap hack. */
if (X.IRQlow & FCEU_IQEXT) ret |= 1;
@@ -266,7 +266,7 @@ static DECLFR(FDSRead4030) {
}
static DECLFR(FDSRead4031) {
uint8 ret = 0xff;
uint8_t ret = 0xff;
if (FDS_DISK_INSERTED && mapperFDS_control & 0x04) {
mapperFDS_diskaccess = 1;
@@ -303,7 +303,7 @@ static DECLFR(FDSRead4031) {
}
static DECLFR(FDSRead4032) {
uint8 ret;
uint8_t ret;
ret = X.DB & ~7;
if (InDisk == 255)
@@ -430,7 +430,7 @@ static DECLFW(FDSWrite) {
}
struct codes_t {
uint8 code;
uint8_t code;
char *name;
};
@@ -574,7 +574,7 @@ static const struct codes_t list[] = {
{ 0 }
};
static const char *getManufacturer(uint8 code)
static const char *getManufacturer(uint8_t code)
{
int x = 0;
char *ret = "unlicensed";
@@ -607,9 +607,9 @@ static void FreeFDSMemory(void) {
static int SubLoad(FCEUFILE *fp) {
struct md5_context md5;
uint8 header[16];
uint8_t header[16];
int x;
uint64 fsize = FCEU_fgetsize(fp);
uint64_t fsize = FCEU_fgetsize(fp);
/* Reject files too short to contain a 16-byte header. Otherwise the
* subsequent FCEU_fread leaves header[] partially uninitialised, and
@@ -637,7 +637,7 @@ static int SubLoad(FCEUFILE *fp) {
if (TotalSides < 1) TotalSides = 1;
FDSROMSize = TotalSides * BYTES_PER_SIDE;
FDSROM = (uint8*)FCEU_malloc(FDSROMSize);
FDSROM = (uint8_t*)FCEU_malloc(FDSROMSize);
if (!FDSROM)
return (0);
@@ -693,7 +693,7 @@ int FDSLoad(const char *name, FCEUFILE *fp) {
ResetCartMapping();
FDSBIOSsize = 8192;
FDSBIOS = (uint8*)FCEU_gmalloc(FDSBIOSsize);
FDSBIOS = (uint8_t*)FCEU_gmalloc(FDSBIOSsize);
SetupCartPRGMapping(0, FDSBIOS, FDSBIOSsize, 0);
if (FCEU_fread(FDSBIOS, 1, FDSBIOSsize, zp) != FDSBIOSsize) {
@@ -718,7 +718,7 @@ int FDSLoad(const char *name, FCEUFILE *fp) {
}
for (x = 0; x < TotalSides; x++) {
diskdatao[x] = (uint8*)FCEU_malloc(65500);
diskdatao[x] = (uint8_t*)FCEU_malloc(65500);
if (!diskdatao[x]) {
int y;
for (y = 0; y < x; y++) {
@@ -777,12 +777,12 @@ int FDSLoad(const char *name, FCEUFILE *fp) {
AddExState(&mapperFDS_diskaccess, 1, 0, "DACC");
CHRRAMSize = 8192;
CHRRAM = (uint8*)FCEU_gmalloc(CHRRAMSize);
CHRRAM = (uint8_t*)FCEU_gmalloc(CHRRAMSize);
SetupCartCHRMapping(0, CHRRAM, CHRRAMSize, 1);
AddExState(CHRRAM, CHRRAMSize, 0, "CHRR");
FDSRAMSize = 32768;
FDSRAM = (uint8*)FCEU_gmalloc(FDSRAMSize);
FDSRAM = (uint8_t*)FCEU_gmalloc(FDSRAMSize);
SetupCartPRGMapping(1, FDSRAM, FDSRAMSize, 1);
AddExState(FDSRAM, FDSRAMSize, 0, "FDSR");