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Diffstat (limited to 'sync.c')
| -rw-r--r-- | sync.c | 133 |
1 files changed, 133 insertions, 0 deletions
@@ -0,0 +1,133 @@ +/* ----------------------------------------------------------------------- * + * + * Copyright 1996-2009 The NASM Authors - All Rights Reserved + * See the file AUTHORS included with the NASM distribution for + * the specific copyright holders. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following + * conditions are met: + * + * * Redistributions of source code must retain the above copyright + * notice, this list of conditions and the following disclaimer. + * * Redistributions in binary form must reproduce the above + * copyright notice, this list of conditions and the following + * disclaimer in the documentation and/or other materials provided + * with the distribution. + * + * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND + * CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, + * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF + * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE + * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR + * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, + * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT + * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; + * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) + * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN + * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR + * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, + * EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. + * + * ----------------------------------------------------------------------- */ + +/* + * sync.c the Netwide Disassembler synchronisation processing module + */ + +#include "compiler.h" + +#include <stdio.h> +#include <stdlib.h> +#include <limits.h> +#include <inttypes.h> + +#include "nasmlib.h" +#include "sync.h" + +#define SYNC_MAX_SHIFT 31 +#define SYNC_MAX_SIZE (1U << SYNC_MAX_SHIFT) + +/* initial # of sync points (*must* be power of two)*/ +#define SYNC_INITIAL_CHUNK (1U << 12) + +/* + * This lot manages the current set of sync points by means of a + * heap (priority queue) structure. + */ + +static struct Sync { + uint32_t pos; + uint32_t length; +} *synx; + +static uint32_t max_synx, nsynx; + +static inline void swap_sync(uint32_t dst, uint32_t src) +{ + struct Sync t = synx[dst]; + synx[dst] = synx[src]; + synx[src] = t; +} + +void init_sync(void) +{ + max_synx = SYNC_INITIAL_CHUNK; + synx = nasm_malloc((max_synx + 1) * sizeof(*synx)); + nsynx = 0; +} + +void add_sync(uint32_t pos, uint32_t length) +{ + uint32_t i; + + if (nsynx >= max_synx) { + if (max_synx >= SYNC_MAX_SIZE) /* too many sync points! */ + return; + max_synx = (max_synx << 1); + synx = nasm_realloc(synx, (max_synx + 1) * sizeof(*synx)); + } + + nsynx++; + synx[nsynx].pos = pos; + synx[nsynx].length = length; + + for (i = nsynx; i > 1; i /= 2) { + if (synx[i / 2].pos > synx[i].pos) + swap_sync(i / 2, i); + } +} + +uint32_t next_sync(uint32_t position, uint32_t *length) +{ + while (nsynx > 0 && synx[1].pos + synx[1].length <= position) { + uint32_t i, j; + + swap_sync(nsynx, 1); + nsynx--; + + i = 1; + while (i * 2 <= nsynx) { + j = i * 2; + if (synx[j].pos < synx[i].pos && + (j + 1 > nsynx || synx[j + 1].pos > synx[j].pos)) { + swap_sync(j, i); + i = j; + } else if (j + 1 <= nsynx && synx[j + 1].pos < synx[i].pos) { + swap_sync(j + 1, i); + i = j + 1; + } else + break; + } + } + + if (nsynx > 0) { + if (length) + *length = synx[1].length; + return synx[1].pos; + } else { + if (length) + *length = 0L; + return 0; + } +} |