246 lines
8.0 KiB
C
246 lines
8.0 KiB
C
/*
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* Align bytecode
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*
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* Copyright (C) 2005-2007 Peter Johnson
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND OTHER CONTRIBUTORS ``AS IS''
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* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR OTHER CONTRIBUTORS BE
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* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
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* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
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* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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* POSSIBILITY OF SUCH DAMAGE.
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*/
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#include "util.h"
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#include "libyasm-stdint.h"
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#include "coretype.h"
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#include "errwarn.h"
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#include "intnum.h"
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#include "expr.h"
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#include "bytecode.h"
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typedef struct bytecode_align {
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/*@only@*/ yasm_expr *boundary; /* alignment boundary */
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/* What to fill intervening locations with, NULL if using code_fill */
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/*@only@*/ /*@null@*/ yasm_expr *fill;
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/* Maximum number of bytes to skip, NULL if no maximum. */
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/*@only@*/ /*@null@*/ yasm_expr *maxskip;
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/* Code fill, NULL if using 0 fill */
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/*@null@*/ const unsigned char **code_fill;
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} bytecode_align;
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static void bc_align_destroy(void *contents);
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static void bc_align_print(const void *contents, FILE *f, int indent_level);
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static void bc_align_finalize(yasm_bytecode *bc, yasm_bytecode *prev_bc);
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static int bc_align_calc_len(yasm_bytecode *bc, yasm_bc_add_span_func add_span,
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void *add_span_data);
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static int bc_align_expand(yasm_bytecode *bc, int span, long old_val,
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long new_val, /*@out@*/ long *neg_thres,
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/*@out@*/ long *pos_thres);
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static int bc_align_tobytes(yasm_bytecode *bc, unsigned char **bufp,
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unsigned char *bufstart, void *d,
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yasm_output_value_func output_value,
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/*@null@*/ yasm_output_reloc_func output_reloc);
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static const yasm_bytecode_callback bc_align_callback = {
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bc_align_destroy,
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bc_align_print,
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bc_align_finalize,
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NULL,
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bc_align_calc_len,
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bc_align_expand,
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bc_align_tobytes,
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YASM_BC_SPECIAL_OFFSET
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};
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static void
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bc_align_destroy(void *contents)
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{
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bytecode_align *align = (bytecode_align *)contents;
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if (align->boundary)
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yasm_expr_destroy(align->boundary);
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if (align->fill)
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yasm_expr_destroy(align->fill);
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if (align->maxskip)
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yasm_expr_destroy(align->maxskip);
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yasm_xfree(contents);
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}
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static void
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bc_align_print(const void *contents, FILE *f, int indent_level)
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{
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const bytecode_align *align = (const bytecode_align *)contents;
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fprintf(f, "%*s_Align_\n", indent_level, "");
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fprintf(f, "%*sBoundary=", indent_level, "");
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yasm_expr_print(align->boundary, f);
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fprintf(f, "\n%*sFill=", indent_level, "");
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yasm_expr_print(align->fill, f);
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fprintf(f, "\n%*sMax Skip=", indent_level, "");
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yasm_expr_print(align->maxskip, f);
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fprintf(f, "\n");
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}
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static void
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bc_align_finalize(yasm_bytecode *bc, yasm_bytecode *prev_bc)
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{
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bytecode_align *align = (bytecode_align *)bc->contents;
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if (!yasm_expr_get_intnum(&align->boundary, 0))
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yasm_error_set(YASM_ERROR_NOT_CONSTANT,
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N_("align boundary must be a constant"));
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if (align->fill && !yasm_expr_get_intnum(&align->fill, 0))
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yasm_error_set(YASM_ERROR_NOT_CONSTANT,
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N_("align fill must be a constant"));
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if (align->maxskip && !yasm_expr_get_intnum(&align->maxskip, 0))
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yasm_error_set(YASM_ERROR_NOT_CONSTANT,
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N_("align maximum skip must be a constant"));
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}
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static int
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bc_align_calc_len(yasm_bytecode *bc, yasm_bc_add_span_func add_span,
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void *add_span_data)
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{
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long neg_thres = 0;
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long pos_thres = 0;
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if (bc_align_expand(bc, 0, 0, (long)bc->offset, &neg_thres,
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&pos_thres) < 0)
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return -1;
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return 0;
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}
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static int
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bc_align_expand(yasm_bytecode *bc, int span, long old_val, long new_val,
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/*@out@*/ long *neg_thres, /*@out@*/ long *pos_thres)
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{
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bytecode_align *align = (bytecode_align *)bc->contents;
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unsigned long end;
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unsigned long boundary =
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yasm_intnum_get_uint(yasm_expr_get_intnum(&align->boundary, 0));
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if (boundary == 0) {
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bc->len = 0;
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*pos_thres = new_val;
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return 0;
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}
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end = (unsigned long)new_val;
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if ((unsigned long)new_val & (boundary-1))
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end = ((unsigned long)new_val & ~(boundary-1)) + boundary;
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*pos_thres = (long)end;
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bc->len = end - (unsigned long)new_val;
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if (align->maxskip) {
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unsigned long maxskip =
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yasm_intnum_get_uint(yasm_expr_get_intnum(&align->maxskip, 0));
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if (bc->len > maxskip) {
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*pos_thres = (long)end-maxskip-1;
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bc->len = 0;
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}
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}
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return 1;
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}
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static int
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bc_align_tobytes(yasm_bytecode *bc, unsigned char **bufp,
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unsigned char *bufstart, void *d,
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yasm_output_value_func output_value,
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/*@unused@*/ yasm_output_reloc_func output_reloc)
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{
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bytecode_align *align = (bytecode_align *)bc->contents;
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unsigned long len;
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unsigned long boundary =
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yasm_intnum_get_uint(yasm_expr_get_intnum(&align->boundary, 0));
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if (boundary == 0)
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return 0;
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else {
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unsigned long end = bc->offset;
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if (bc->offset & (boundary-1))
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end = (bc->offset & ~(boundary-1)) + boundary;
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len = end - bc->offset;
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if (len == 0)
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return 0;
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if (align->maxskip) {
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unsigned long maxskip =
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yasm_intnum_get_uint(yasm_expr_get_intnum(&align->maxskip, 0));
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if (len > maxskip)
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return 0;
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}
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}
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if (align->fill) {
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unsigned long v;
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v = yasm_intnum_get_uint(yasm_expr_get_intnum(&align->fill, 0));
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memset(*bufp, (int)v, len);
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*bufp += len;
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} else if (align->code_fill) {
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unsigned long maxlen = 15;
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while (!align->code_fill[maxlen] && maxlen>0)
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maxlen--;
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if (maxlen == 0) {
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yasm_error_set(YASM_ERROR_GENERAL,
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N_("could not find any code alignment size"));
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return 1;
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}
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/* Fill with maximum code fill as much as possible */
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while (len > maxlen) {
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memcpy(*bufp, align->code_fill[maxlen], maxlen);
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*bufp += maxlen;
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len -= maxlen;
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}
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if (!align->code_fill[len]) {
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yasm_error_set(YASM_ERROR_VALUE,
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N_("invalid alignment size %d"), len);
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return 1;
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}
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/* Handle rest of code fill */
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memcpy(*bufp, align->code_fill[len], len);
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*bufp += len;
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} else {
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/* Just fill with 0 */
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memset(*bufp, 0, len);
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*bufp += len;
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}
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return 0;
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}
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yasm_bytecode *
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yasm_bc_create_align(yasm_expr *boundary, yasm_expr *fill,
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yasm_expr *maxskip, const unsigned char **code_fill,
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unsigned long line)
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{
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bytecode_align *align = yasm_xmalloc(sizeof(bytecode_align));
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align->boundary = boundary;
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align->fill = fill;
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align->maxskip = maxskip;
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align->code_fill = code_fill;
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return yasm_bc_create_common(&bc_align_callback, align, line);
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}
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