Chameleon

Chameleon Commit Details

Date:2010-08-01 02:36:56 (13 years 8 months ago)
Author:Tamás Kosárszky
Commit:292
Parents: 291
Message:Added cache support for FAT filesystems. Now booting from an average speed flash drive formatted to FAT32 fs using 512 byte cluster size is about 50 times faster.
Changes:
M/trunk/i386/libsaio/cache.c
M/trunk/i386/libsaio/msdos.c

File differences

trunk/i386/libsaio/cache.c
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␊
#define kCacheSize (0x100000)␊
#define kCacheMinBlockSize (0x200)␊
#define kCacheMaxBlockSize (0x4000)␊
#define kCacheMaxBlockSize (0x8000)␊
#define kCacheMaxEntries (kCacheSize / kCacheMinBlockSize)␊
␊
static CICell gCacheIH;␊
#endif␊
␊
if ((blockSize < kCacheMinBlockSize) ||␊
(blockSize >= kCacheMaxBlockSize))␊
(blockSize > kCacheMaxBlockSize))␊
return;␊
␊
gCacheBlockSize = blockSize;␊
trunk/i386/libsaio/msdos.c
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␊
#define LABEL_LENGTH␉␉11␊
#define MAX_DOS_BLOCKSIZE␉2048␊
#define MAX_CACHE_BLOCKSIZE 32768␊
␊
#define␉CLUST_FIRST␉␉2/* reserved cluster range */␊
#define␉CLUST_RSRVD32␉0x0ffffff8␉/* reserved cluster range */␊
static CICell msdoscurrent = 0;␊
static int msdosrootcluster = 0;␊
static int msdosfatbits = 0;␊
static int msdosCacheBlockSize = 0;␊
␊
#if UNUSED␊
/*␊
␉␊
␉if (msdoscurrent == ih)␊
␉{␊
␉␉CacheInit(ih, msdosclustersize);␊
␉␉CacheInit(ih, msdosCacheBlockSize);␊
␉␉return 0;␊
␉}␊
␉␊
␉}␊
␉␊
␉msdosclustersize = msdosbps * spc;␊
␊
␉msdoscurrent = ih;␊
␉CacheInit(ih, msdosclustersize);␊
␉␊
␉msdosCacheBlockSize = (msdosclustersize > MAX_CACHE_BLOCKSIZE) ? msdosclustersize : MAX_CACHE_BLOCKSIZE;␊
␉CacheInit(ih, msdosCacheBlockSize);␊
␉free (buf);␊
␉return 0;␊
}␊
␊
static int␊
readSectorAligned(CICell ih, off_t readOffset, char *buf, int size)␊
{␊
long long sectorOffset = (uint64_t)readOffset / msdosCacheBlockSize * msdosCacheBlockSize;␊
long relOffset = readOffset % msdosCacheBlockSize;␊
char *cacheBuffer;␊
␊
cacheBuffer = malloc(msdosCacheBlockSize);␊
CacheRead(ih, cacheBuffer, sectorOffset, msdosCacheBlockSize, true);␊
bcopy(cacheBuffer + relOffset, buf, size);␊
free(cacheBuffer);␊
␊
return 0;␊
}␊
␊
static int␊
msdosreadcluster (CICell ih, uint8_t *buf, int size, off_t *cluster)␊
{␊
off_t readOffset;␊
␉/* Read in "cluster" */␊
␉if (buf)␊
␉{␊
␉␉Seek(ih, readOffset);␊
␉␉Read(ih, (long)buf, size);␊
readSectorAligned(ih, readOffset, (char *)buf, size);␊
␉}␊
␉␊
␊
␉/* Find first sector of FAT */␊
␉readOffset = msdosressector*msdosbps;␊
␉readOffset = msdosressector * msdosbps;␊
␊
␉/* Find sector containing "cluster" entry in FAT */␊
␉readOffset += ((uint64_t)*cluster * (uint64_t)msdosfatbits)/8;␊
␉readOffset += ((uint64_t)*cluster * (uint64_t)msdosfatbits) / 8;␊
␉␊
␉/* Read one sector of the FAT */␊
␉Seek(ih, readOffset);␊
␉Read(ih, (long)tmpbuf, 4);␊
␉readSectorAligned(ih, readOffset, tmpbuf, 4);␊
␉␊
␉switch (msdosfatbits) {␊
␉␉case 32:␊

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Revision: 292