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File: [local] / sys / lib / libz / adler32.c (download)
Revision 1.1.1.1 (vendor branch), Tue Mar 4 16:15:15 2008 UTC (16 years, 6 months ago) by nbrk
Import of OpenBSD 4.2 release kernel tree with initial code to support Jornada 720/728, StrongARM 1110-based handheld PC. At this point kernel roots on NFS and boots into vfs_mountroot() and traps. What is supported: - glass console, Jornada framebuffer (jfb) works in 16bpp direct color mode (needs some palette tweaks for non black/white/blue colors, i think) - saic, SA11x0 interrupt controller (needs cleanup) - sacom, SA11x0 UART (supported only as boot console for now) - SA11x0 GPIO controller fully supported (but can't handle multiple interrupt handlers on one gpio pin) - sassp, SSP port on SA11x0 that attaches spibus - Jornada microcontroller (jmcu) to control kbd, battery, etc throught the SPI bus (wskbd attaches on jmcu, but not tested) - tod functions seem work - initial code for SA-1111 (chip companion) : this is TODO Next important steps, i think: - gpio and intc on sa1111 - pcmcia support for sa11x0 (and sa1111 help logic) - REAL root on nfs when we have PCMCIA support (we may use any of supported pccard NICs) - root on wd0! (using already supported PCMCIA-ATA) |
/* $OpenBSD: adler32.c,v 1.9 2006/07/20 11:14:10 mickey Exp $ */ /* adler32.c -- compute the Adler-32 checksum of a data stream * Copyright (C) 1995-2004 Mark Adler * For conditions of distribution and use, see copyright notice in zlib.h */ #define ZLIB_INTERNAL #include "zlib.h" #define BASE 65521UL /* largest prime smaller than 65536 */ #define NMAX 5552 /* NMAX is the largest n such that 255n(n+1)/2 + (n+1)(BASE-1) <= 2^32-1 */ #define DO1(buf,i) {adler += (buf)[i]; sum2 += adler;} #define DO2(buf,i) DO1(buf,i); DO1(buf,i+1); #define DO4(buf,i) DO2(buf,i); DO2(buf,i+2); #define DO8(buf,i) DO4(buf,i); DO4(buf,i+4); #define DO16(buf) DO8(buf,0); DO8(buf,8); /* use NO_DIVIDE if your processor does not do division in hardware */ #ifdef NO_DIVIDE # define MOD(a) \ do { \ if (a >= (BASE << 16)) a -= (BASE << 16); \ if (a >= (BASE << 15)) a -= (BASE << 15); \ if (a >= (BASE << 14)) a -= (BASE << 14); \ if (a >= (BASE << 13)) a -= (BASE << 13); \ if (a >= (BASE << 12)) a -= (BASE << 12); \ if (a >= (BASE << 11)) a -= (BASE << 11); \ if (a >= (BASE << 10)) a -= (BASE << 10); \ if (a >= (BASE << 9)) a -= (BASE << 9); \ if (a >= (BASE << 8)) a -= (BASE << 8); \ if (a >= (BASE << 7)) a -= (BASE << 7); \ if (a >= (BASE << 6)) a -= (BASE << 6); \ if (a >= (BASE << 5)) a -= (BASE << 5); \ if (a >= (BASE << 4)) a -= (BASE << 4); \ if (a >= (BASE << 3)) a -= (BASE << 3); \ if (a >= (BASE << 2)) a -= (BASE << 2); \ if (a >= (BASE << 1)) a -= (BASE << 1); \ if (a >= BASE) a -= BASE; \ } while (0) # define MOD4(a) \ do { \ if (a >= (BASE << 4)) a -= (BASE << 4); \ if (a >= (BASE << 3)) a -= (BASE << 3); \ if (a >= (BASE << 2)) a -= (BASE << 2); \ if (a >= (BASE << 1)) a -= (BASE << 1); \ if (a >= BASE) a -= BASE; \ } while (0) #else # define MOD(a) a %= BASE # define MOD4(a) a %= BASE #endif /* ========================================================================= */ uLong ZEXPORT adler32(adler, buf, len) uLong adler; const Bytef *buf; uInt len; { unsigned long sum2; unsigned n; /* split Adler-32 into component sums */ sum2 = (adler >> 16) & 0xffff; adler &= 0xffff; /* in case user likes doing a byte at a time, keep it fast */ if (len == 1) { adler += buf[0]; if (adler >= BASE) adler -= BASE; sum2 += adler; if (sum2 >= BASE) sum2 -= BASE; return adler | (sum2 << 16); } /* initial Adler-32 value (deferred check for len == 1 speed) */ if (buf == Z_NULL) return 1L; /* in case short lengths are provided, keep it somewhat fast */ if (len < 16) { while (len--) { adler += *buf++; sum2 += adler; } if (adler >= BASE) adler -= BASE; MOD4(sum2); /* only added so many BASE's */ return adler | (sum2 << 16); } /* do length NMAX blocks -- requires just one modulo operation */ while (len >= NMAX) { len -= NMAX; n = NMAX / 16; /* NMAX is divisible by 16 */ do { DO16(buf); /* 16 sums unrolled */ buf += 16; } while (--n); MOD(adler); MOD(sum2); } /* do remaining bytes (less than NMAX, still just one modulo) */ if (len) { /* avoid modulos if none remaining */ while (len >= 16) { len -= 16; DO16(buf); buf += 16; } while (len--) { adler += *buf++; sum2 += adler; } MOD(adler); MOD(sum2); } /* return recombined sums */ return adler | (sum2 << 16); } #ifdef ADLER32_COMBINE /* ========================================================================= */ uLong ZEXPORT adler32_combine(adler1, adler2, len2) uLong adler1; uLong adler2; z_off_t len2; { unsigned long sum1; unsigned long sum2; unsigned rem; /* the derivation of this formula is left as an exercise for the reader */ rem = (unsigned)(len2 % BASE); sum1 = adler1 & 0xffff; sum2 = rem * sum1; MOD(sum2); sum1 += (adler2 & 0xffff) + BASE - 1; sum2 += ((adler1 >> 16) & 0xffff) + ((adler2 >> 16) & 0xffff) + BASE - rem; if (sum1 > BASE) sum1 -= BASE; if (sum1 > BASE) sum1 -= BASE; if (sum2 > (BASE << 1)) sum2 -= (BASE << 1); if (sum2 > BASE) sum2 -= BASE; return sum1 | (sum2 << 16); } #endif /* ADLER32_COMBINE */