1/* inffas8664.c is a hand tuned assembler version of inffast.c - fast decoding
  2 * version for AMD64 on Windows using Microsoft C compiler
  3 *
  4 * Copyright (C) 1995-2003 Mark Adler
  5 * For conditions of distribution and use, see copyright notice in zlib.h
  6 *
  7 * Copyright (C) 2003 Chris Anderson <christop@charm.net>
  8 * Please use the copyright conditions above.
  9 *
 10 * 2005 - Adaptation to Microsoft C Compiler for AMD64 by Gilles Vollant
 11 *
 12 * inffas8664.c call function inffas8664fnc in inffasx64.asm
 13 *  inffasx64.asm is automatically convert from AMD64 portion of inffas86.c
 14 *
 15 * Dec-29-2003 -- I added AMD64 inflate asm support.  This version is also
 16 * slightly quicker on x86 systems because, instead of using rep movsb to copy
 17 * data, it uses rep movsw, which moves data in 2-byte chunks instead of single
 18 * bytes.  I've tested the AMD64 code on a Fedora Core 1 + the x86_64 updates
 19 * from http://fedora.linux.duke.edu/fc1_x86_64
 20 * which is running on an Athlon 64 3000+ / Gigabyte GA-K8VT800M system with
 21 * 1GB ram.  The 64-bit version is about 4% faster than the 32-bit version,
 22 * when decompressing mozilla-source-1.3.tar.gz.
 23 *
 24 * Mar-13-2003 -- Most of this is derived from inffast.S which is derived from
 25 * the gcc -S output of zlib-1.2.0/inffast.c.  Zlib-1.2.0 is in beta release at
 26 * the moment.  I have successfully compiled and tested this code with gcc2.96,
 27 * gcc3.2, icc5.0, msvc6.0.  It is very close to the speed of inffast.S
 28 * compiled with gcc -DNO_MMX, but inffast.S is still faster on the P3 with MMX
 29 * enabled.  I will attempt to merge the MMX code into this version.  Newer
 30 * versions of this and inffast.S can be found at
 31 * http://www.eetbeetee.com/zlib/ and http://www.charm.net/~christop/zlib/
 32 *
 33 */
 34
 35#include <stdio.h>
 36#include "zutil.h"
 37#include "inftrees.h"
 38#include "inflate.h"
 39#include "inffast.h"
 40
 41/* Mark Adler's comments from inffast.c: */
 42
 43/*
 44   Decode literal, length, and distance codes and write out the resulting
 45   literal and match bytes until either not enough input or output is
 46   available, an end-of-block is encountered, or a data error is encountered.
 47   When large enough input and output buffers are supplied to inflate(), for
 48   example, a 16K input buffer and a 64K output buffer, more than 95% of the
 49   inflate execution time is spent in this routine.
 50
 51   Entry assumptions:
 52
 53        state->mode == LEN
 54        strm->avail_in >= 6
 55        strm->avail_out >= 258
 56        start >= strm->avail_out
 57        state->bits < 8
 58
 59   On return, state->mode is one of:
 60
 61        LEN -- ran out of enough output space or enough available input
 62        TYPE -- reached end of block code, inflate() to interpret next block
 63        BAD -- error in block data
 64
 65   Notes:
 66
 67    - The maximum input bits used by a length/distance pair is 15 bits for the
 68      length code, 5 bits for the length extra, 15 bits for the distance code,
 69      and 13 bits for the distance extra.  This totals 48 bits, or six bytes.
 70      Therefore if strm->avail_in >= 6, then there is enough input to avoid
 71      checking for available input while decoding.
 72
 73    - The maximum bytes that a single length/distance pair can output is 258
 74      bytes, which is the maximum length that can be coded.  inflate_fast()
 75      requires strm->avail_out >= 258 for each loop to avoid checking for
 76      output space.
 77 */
 78
 79
 80
 81    typedef struct inffast_ar {
 82/* 64   32                               x86  x86_64 */
 83/* ar offset                              register */
 84/*  0    0 */ void *esp;                /* esp save */
 85/*  8    4 */ void *ebp;                /* ebp save */
 86/* 16    8 */ unsigned char FAR *in;    /* esi rsi  local strm->next_in */
 87/* 24   12 */ unsigned char FAR *last;  /*     r9   while in < last */
 88/* 32   16 */ unsigned char FAR *out;   /* edi rdi  local strm->next_out */
 89/* 40   20 */ unsigned char FAR *beg;   /*          inflate()'s init next_out */
 90/* 48   24 */ unsigned char FAR *end;   /*     r10  while out < end */
 91/* 56   28 */ unsigned char FAR *window;/*          size of window, wsize!=0 */
 92/* 64   32 */ code const FAR *lcode;    /* ebp rbp  local strm->lencode */
 93/* 72   36 */ code const FAR *dcode;    /*     r11  local strm->distcode */
 94/* 80   40 */ size_t /*unsigned long */hold;       /* edx rdx  local strm->hold */
 95/* 88   44 */ unsigned bits;            /* ebx rbx  local strm->bits */
 96/* 92   48 */ unsigned wsize;           /*          window size */
 97/* 96   52 */ unsigned write;           /*          window write index */
 98/*100   56 */ unsigned lmask;           /*     r12  mask for lcode */
 99/*104   60 */ unsigned dmask;           /*     r13  mask for dcode */
100/*108   64 */ unsigned len;             /*     r14  match length */
101/*112   68 */ unsigned dist;            /*     r15  match distance */
102/*116   72 */ unsigned status;          /*          set when state chng*/
103    } type_ar;
104#ifdef ASMINF
105
106void inflate_fast(strm, start)
107z_streamp strm;
108unsigned start;         /* inflate()'s starting value for strm->avail_out */
109{
110    struct inflate_state FAR *state;
111    type_ar ar;
112    void inffas8664fnc(struct inffast_ar * par);
113
114
115
116#if (defined( __GNUC__ ) && defined( __amd64__ ) && ! defined( __i386 )) || (defined(_MSC_VER) && defined(_M_AMD64))
117#define PAD_AVAIL_IN 6
118#define PAD_AVAIL_OUT 258
119#else
120#define PAD_AVAIL_IN 5
121#define PAD_AVAIL_OUT 257
122#endif
123
124    /* copy state to local variables */
125    state = (struct inflate_state FAR *)strm->state;
126
127    ar.in = strm->next_in;
128    ar.last = ar.in + (strm->avail_in - PAD_AVAIL_IN);
129    ar.out = strm->next_out;
130    ar.beg = ar.out - (start - strm->avail_out);
131    ar.end = ar.out + (strm->avail_out - PAD_AVAIL_OUT);
132    ar.wsize = state->wsize;
133    ar.write = state->wnext;
134    ar.window = state->window;
135    ar.hold = state->hold;
136    ar.bits = state->bits;
137    ar.lcode = state->lencode;
138    ar.dcode = state->distcode;
139    ar.lmask = (1U << state->lenbits) - 1;
140    ar.dmask = (1U << state->distbits) - 1;
141
142    /* decode literals and length/distances until end-of-block or not enough
143       input data or output space */
144
145    /* align in on 1/2 hold size boundary */
146    while (((size_t)(void *)ar.in & (sizeof(ar.hold) / 2 - 1)) != 0) {
147        ar.hold += (unsigned long)*ar.in++ << ar.bits;
148        ar.bits += 8;
149    }
150
151    inffas8664fnc(&ar);
152
153    if (ar.status > 1) {
154        if (ar.status == 2)
155            strm->msg = "invalid literal/length code";
156        else if (ar.status == 3)
157            strm->msg = "invalid distance code";
158        else
159            strm->msg = "invalid distance too far back";
160        state->mode = BAD;
161    }
162    else if ( ar.status == 1 ) {
163        state->mode = TYPE;
164    }
165
166    /* return unused bytes (on entry, bits < 8, so in won't go too far back) */
167    ar.len = ar.bits >> 3;
168    ar.in -= ar.len;
169    ar.bits -= ar.len << 3;
170    ar.hold &= (1U << ar.bits) - 1;
171
172    /* update state and return */
173    strm->next_in = ar.in;
174    strm->next_out = ar.out;
175    strm->avail_in = (unsigned)(ar.in < ar.last ?
176                                PAD_AVAIL_IN + (ar.last - ar.in) :
177                                PAD_AVAIL_IN - (ar.in - ar.last));
178    strm->avail_out = (unsigned)(ar.out < ar.end ?
179                                 PAD_AVAIL_OUT + (ar.end - ar.out) :
180                                 PAD_AVAIL_OUT - (ar.out - ar.end));
181    state->hold = (unsigned long)ar.hold;
182    state->bits = ar.bits;
183    return;
184}
185
186#endif