* doc/c-cris.texi (CRIS-Opts): Document --no-mul-bug-abort,
--mul-bug-abort and the default behavior. * config/tc-cris.c (cris_insn_kind): New member CRIS_INSN_MUL. (err_for_dangerous_mul_placement): New variable. (STATE_MUL, OPTION_MULBUG_ABORT_ON, OPTION_MULBUG_ABORT_OFF): New macros. (md_cris_relax_table): Have placeholder for STATE_MUL. (md_longopts): New options --mul-bug-abort and --no-mul-bug-abort. (cris_relax_frag) <case ENCODE_RELAX (STATE_MUL, STATE_BYTE)>: New case doing nothing. (md_estimate_size_before_relax) <case ENCODE_RELAX (STATE_MUL, STATE_BYTE)>: Ditto. (md_convert_frag) <ENCODE_RELAX (STATE_MUL, STATE_BYTE)>: Check alignment and position of this frag, emit error message if suspicious. (md_assemble): For a multiply insn and when checking it, transform the current frag into a special frag for that purpose. (md_parse_option) <case OPTION_MULBUG_ABORT_OFF, case OPTION_MULBUG_ABORT_ON>: Handle new options.
This commit is contained in:
Hans-Peter Nilsson
parent
95631471e2
commit
1048a9ba65
3 changed files with 108 additions and 3 deletions
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@ -1,3 +1,25 @@
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2004-03-22 Hans-Peter Nilsson <hp@axis.com>
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* doc/c-cris.texi (CRIS-Opts): Document --no-mul-bug-abort,
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--mul-bug-abort and the default behavior.
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* config/tc-cris.c (cris_insn_kind): New member CRIS_INSN_MUL.
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(err_for_dangerous_mul_placement): New variable.
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(STATE_MUL, OPTION_MULBUG_ABORT_ON, OPTION_MULBUG_ABORT_OFF): New
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macros.
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(md_cris_relax_table): Have placeholder for STATE_MUL.
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(md_longopts): New options --mul-bug-abort and --no-mul-bug-abort.
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(cris_relax_frag) <case ENCODE_RELAX (STATE_MUL, STATE_BYTE)>: New
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case doing nothing.
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(md_estimate_size_before_relax) <case ENCODE_RELAX (STATE_MUL,
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STATE_BYTE)>: Ditto.
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(md_convert_frag) <ENCODE_RELAX (STATE_MUL, STATE_BYTE)>: Check
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alignment and position of this frag, emit error message if
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suspicious.
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(md_assemble): For a multiply insn and when checking it,
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transform the current frag into a special frag for that purpose.
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(md_parse_option) <case OPTION_MULBUG_ABORT_OFF, case
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OPTION_MULBUG_ABORT_ON>: Handle new options.
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2004-03-19 Bob Wilson <bob.wilson@acm.org>
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* config/tc-xtensa.c (mark_literal_frags): New function.
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@ -58,7 +58,7 @@
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Note that some prefix-insns might be assembled as CRIS_INSN_NORMAL. */
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enum cris_insn_kind
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{
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CRIS_INSN_NORMAL, CRIS_INSN_NONE, CRIS_INSN_BRANCH
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CRIS_INSN_NORMAL, CRIS_INSN_NONE, CRIS_INSN_BRANCH, CRIS_INSN_MUL
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};
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/* An instruction will have one of these prefixes.
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@ -187,6 +187,10 @@ const pseudo_typeS md_pseudo_table[] =
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static int warn_for_branch_expansion = 0;
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/* Whether to emit error when a MULS/MULU could be located last on a
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cache-line. */
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static int err_for_dangerous_mul_placement = 1;
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const char cris_comment_chars[] = ";";
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/* This array holds the chars that only start a comment at the beginning of
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@ -219,10 +223,16 @@ const char FLT_CHARS[] = "";
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length: byte, word, 10-byte expansion
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2. BDAP
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length: byte, word, dword */
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length: byte, word, dword
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3. MULS/MULU
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Not really a relaxation (no infrastructure to get delay-slots
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right), just an alignment and placement checker for the v10
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multiply/cache-bug. */
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#define STATE_CONDITIONAL_BRANCH (1)
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#define STATE_BASE_PLUS_DISP_PREFIX (2)
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#define STATE_MUL (3)
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#define STATE_LENGTH_MASK (3)
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#define STATE_BYTE (0)
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@ -282,7 +292,13 @@ const relax_typeS md_cris_relax_table[] =
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{BDAP_WF, BDAP_WB, 2, ENCODE_RELAX (2, 2)},
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/* BDAP.d [PC+] (2, 2). */
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{0, 0, 4, 0}
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{0, 0, 4, 0},
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/* Unused (2, 3). */
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{0, 0, 0, 0},
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/* MULS/MULU (3, 0). Positions (3, 1..3) are unused. */
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{0, 0, 0, 0}, {0, 0, 0, 0}, {0, 0, 0, 0}, {0, 0, 0, 0}
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};
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#undef BRANCH_BF
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@ -304,6 +320,10 @@ struct option md_longopts[] =
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{"underscore", no_argument, NULL, OPTION_US},
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#define OPTION_PIC (OPTION_MD_BASE + 2)
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{"pic", no_argument, NULL, OPTION_PIC},
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#define OPTION_MULBUG_ABORT_ON (OPTION_MD_BASE + 3)
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{"mul-bug-abort", no_argument, NULL, OPTION_MULBUG_ABORT_ON},
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#define OPTION_MULBUG_ABORT_OFF (OPTION_MD_BASE + 4)
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{"no-mul-bug-abort", no_argument, NULL, OPTION_MULBUG_ABORT_OFF},
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{NULL, no_argument, NULL, 0}
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};
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@ -392,6 +412,10 @@ cris_relax_frag (seg, fragP, stretch)
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aim = S_GET_VALUE (symbolP);
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break;
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case ENCODE_RELAX (STATE_MUL, STATE_BYTE):
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/* Nothing to do here. */
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return 0;
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default:
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as_fatal (_("internal inconsistency problem in %s: fr_subtype %d"),
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__FUNCTION__, fragP->fr_subtype);
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@ -558,6 +582,10 @@ md_estimate_size_before_relax (fragP, segment_type)
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fragP->fr_var = md_cris_relax_table[fragP->fr_subtype].rlx_length;
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break;
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case ENCODE_RELAX (STATE_MUL, STATE_BYTE):
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/* Nothing to do here. */
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break;
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default:
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BAD_CASE (fragP->fr_subtype);
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}
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@ -679,6 +707,24 @@ md_convert_frag (abfd, sec, fragP)
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var_part_size = 4;
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break;
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case ENCODE_RELAX (STATE_MUL, STATE_BYTE):
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/* This is the only time we check position and aligmnent of the
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placement-tracking frag. */
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if (sec->alignment_power < 2)
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as_bad_where (fragP->fr_file, fragP->fr_line,
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_("section alignment must be >= 4 bytes to check MULS/MULU safeness"));
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else
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{
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/* If the address after the MULS/MULU has alignment which is
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that of the section and may be that of a cache-size of the
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buggy versions, then the MULS/MULU can be placed badly. */
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if ((address_of_var_part
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& ((1 << sec->alignment_power) - 1) & 31) == 0)
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as_bad_where (fragP->fr_file, fragP->fr_line,
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_("dangerous MULS/MULU location; give it higher alignment"));
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}
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break;
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default:
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BAD_CASE (fragP->fr_subtype);
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break;
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@ -967,6 +1013,13 @@ md_assemble (str)
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output_instruction.expr.X_add_number);
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}
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}
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else if (output_instruction.insn_type == CRIS_INSN_MUL
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&& err_for_dangerous_mul_placement)
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/* Create a frag which which we track the location of the mul insn
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(in the last two bytes before the mul-frag). */
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frag_variant (rs_machine_dependent, 0, 0,
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ENCODE_RELAX (STATE_MUL, STATE_BYTE),
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NULL, 0, opcodep);
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else
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{
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if (output_instruction.imm_oprnd_size > 0)
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@ -1572,6 +1625,9 @@ cris_process_instruction (insn_text, out_insnp, prefixp)
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!= (unsigned int) out_insnp->imm_oprnd_size))
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as_bad (_("PIC relocation size does not match operand size"));
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}
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else if (instruction->op == cris_muls_op
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|| instruction->op == cris_mulu_op)
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out_insnp->insn_type = CRIS_INSN_MUL;
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}
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break;
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}
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@ -2947,6 +3003,14 @@ md_parse_option (arg, argp)
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pic = TRUE;
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return 1;
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case OPTION_MULBUG_ABORT_OFF:
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err_for_dangerous_mul_placement = 0;
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return 1;
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case OPTION_MULBUG_ABORT_ON:
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err_for_dangerous_mul_placement = 1;
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return 1;
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default:
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return 0;
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}
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@ -74,6 +74,25 @@ When @option{-N} is specified, @code{@value{AS}} will emit a
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warning when a 16-bit branch instruction is expanded into a
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32-bit multiple-instruction construct (@pxref{CRIS-Expand}).
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@cindex @option{--no-mul-bug-abort} command line option, CRIS
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@cindex @option{--mul-bug-abort} command line option, CRIS
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@cindex CRIS @option{--no-mul-bug-abort} command line option
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@cindex CRIS @option{--mul-bug-abort} command line option
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Some versions of the CRIS v10, for example in the Etrax 100 LX,
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contain a bug that causes destabilizing memory accesses when a
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multiply instruction is executed with certain values in the
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first operand just before a cache-miss. When the
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@option{--mul-bug-abort} command line option is active (the
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default value), @code{@value{AS}} will refuse to assemble a file
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containing a multiply instruction at a dangerous offset, one
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that could be the last on a cache-line, or is in a section with
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insufficient alignment. This placement checking does not catch
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any case where the multiply instruction is dangerously placed
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because it is located in a delay-slot. The
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@option{--mul-bug-abort} command line option turns off the
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checking.
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@node CRIS-Expand
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@section Instruction expansion
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