From: Michael Meissner Date: Tue, 16 Dec 1997 13:25:59 +0000 (+0000) Subject: Better optimize parallel instructions X-Git-Url: http://drtracing.org/?a=commitdiff_plain;h=e0882f340d95d41ac73a7642618bca517b5ee07c;p=deliverable%2Fbinutils-gdb.git Better optimize parallel instructions --- diff --git a/gas/ChangeLog b/gas/ChangeLog index 08b8ef7026..1b0c420081 100644 --- a/gas/ChangeLog +++ b/gas/ChangeLog @@ -1,3 +1,17 @@ +start-sanitize-d30v +Tue Dec 16 15:26:03 1997 Michael Meissner + + * config/tc-d30v.c (parallel_ok): Remove non-register bits from + used/set flag fields. Make flag vars unsigned long. Use + FLAG_A{0,1} for accumulators. Allow any 2 insns to be done in + parallel if they use the same conditional flag with reversed + meaning. Allow 2 add/sub insns that set the carry or overflow + flags but do not query them to be done in parallel. Don't allow 2 + word store operations to be done in parallel with ADDppp or + SUBppp. Don't allow loads to be done in parallel with 16 bit + multiplies. + +end-sanitize-d30v Tue Dec 16 09:20:43 1997 Nick Clifton * config/tc-arm.c: Prevent use of interworking support for diff --git a/gas/config/tc-d30v.c b/gas/config/tc-d30v.c index 1739059c2b..4185d2ebe9 100644 --- a/gas/config/tc-d30v.c +++ b/gas/config/tc-d30v.c @@ -34,6 +34,9 @@ const char FLT_CHARS[] = "dD"; int Optimizing = 0; +#define FORCE_SHORT 1 +#define FORCE_LONG 2 + /* fixups */ #define MAX_INSN_FIXUPS (5) struct d30v_fixup @@ -62,13 +65,13 @@ static int check_range PARAMS ((unsigned long num, int bits, int flags)); static int postfix PARAMS ((char *p)); static bfd_reloc_code_real_type get_reloc PARAMS ((struct d30v_operand *op, int rel_flag)); static int get_operands PARAMS ((expressionS exp[], int cmp_hack)); -static struct d30v_format *find_format PARAMS ((struct d30v_opcode *opcode, expressionS ops[], - int cmp_hack)); +static struct d30v_format *find_format PARAMS ((struct d30v_opcode *opcode, + expressionS ops[],int fsize, int cmp_hack)); static long long build_insn PARAMS ((struct d30v_insn *opcode, expressionS *opers)); static void write_long PARAMS ((struct d30v_insn *opcode, long long insn, Fixups *fx)); static void write_1_short PARAMS ((struct d30v_insn *opcode, long long insn, Fixups *fx)); static int write_2_short PARAMS ((struct d30v_insn *opcode1, long long insn1, - struct d30v_insn *opcode2, long long insn2, int exec_type, Fixups *fx)); + struct d30v_insn *opcode2, long long insn2, int exec_type, Fixups *fx)); static long long do_assemble PARAMS ((char *str, struct d30v_insn *opcode)); static unsigned long d30v_insert_operand PARAMS (( unsigned long insn, int op_type, offsetT value, int left, fixS *fix)); @@ -76,6 +79,7 @@ static int parallel_ok PARAMS ((struct d30v_insn *opcode1, unsigned long insn1, struct d30v_insn *opcode2, unsigned long insn2, int exec_type)); static void d30v_number_to_chars PARAMS ((char *buf, long long value, int nbytes)); +static void check_size PARAMS ((long value, int bits, char *file, int line)); struct option md_longopts[] = { {NULL, no_argument, NULL, 0} @@ -86,7 +90,9 @@ size_t md_longopts_size = sizeof(md_longopts); /* The target specific pseudo-ops which we support. */ const pseudo_typeS md_pseudo_table[] = { - { NULL, NULL, 0 } + { "word", cons, 4 }, + { "hword", cons, 2 }, + { NULL, NULL, 0 } }; /* Opcode hash table. */ @@ -171,7 +177,7 @@ check_range (num, bits, flags) if (flags & OPERAND_SIGNED) { max = (1 << (bits - 1))-1; - min = - (1 << (bits - 1)); + min = - (1 << (bits - 1)); if (((long)num > max) || ((long)num < min)) retval = 1; } @@ -331,7 +337,11 @@ get_reloc (op, rel_flag) switch (op->bits) { case 6: - return BFD_RELOC_D30V_6; + if (op->flags & OPERAND_SHIFT) + return BFD_RELOC_D30V_9_PCREL; + else + return BFD_RELOC_D30V_6; + break; case 12: if (!(op->flags & OPERAND_SHIFT)) as_warn("unexpected 12-bit reloc type"); @@ -461,43 +471,46 @@ build_insn (opcode, opers) struct d30v_opcode *op = opcode->op; struct d30v_format *form = opcode->form; - /* printf("ecc=%x op1=%x op2=%x mod=%x\n",opcode->ecc,op->op1,op->op2,form->modifier); */ insn = opcode->ecc << 28 | op->op1 << 25 | op->op2 << 20 | form->modifier << 18; - /* printf("insn=%llx\n",insn); */ + for (i=0; form->operands[i]; i++) { flags = d30v_operand_table[form->operands[i]].flags; - /* must be a register or number */ if (!(flags & OPERAND_REG) && !(flags & OPERAND_NUM) && !(flags & OPERAND_NAME) && !(flags & OPERAND_SPECIAL)) continue; bits = d30v_operand_table[form->operands[i]].bits; + if (flags & OPERAND_SHIFT) + bits += 3; + length = d30v_operand_table[form->operands[i]].length; shift = 12 - d30v_operand_table[form->operands[i]].position; - number = opers[i].X_add_number; + if (opers[i].X_op != O_symbol) + number = opers[i].X_add_number; + else + number = 0; if (flags & OPERAND_REG) { - /* now check for mvfsys or mvtsys control registers */ - if (flags & OPERAND_CONTROL && (number & 0x3f) > MAX_CONTROL_REG) + /* check for mvfsys or mvtsys control registers */ + if (flags & OPERAND_CONTROL && (number & 0x7f) > MAX_CONTROL_REG) { /* PSWL or PSWH */ - id = (number & 0x3f) - MAX_CONTROL_REG; - number = 1; + id = (number & 0x7f) - MAX_CONTROL_REG; + number = 0; } else if (number & OPERAND_FLAG) { id = 3; /* number is a flag register */ } - number &= 0x3F; + number &= 0x7F; } else if (flags & OPERAND_SPECIAL) { number = id; } - if (opers[i].X_op != O_register && opers[i].X_op != O_constant && !(flags & OPERAND_NAME)) { @@ -511,7 +524,10 @@ build_insn (opcode, opers) fixups->fix[fixups->fc].size = 4; fixups->fix[fixups->fc].exp = opers[i]; fixups->fix[fixups->fc].operand = form->operands[i]; - fixups->fix[fixups->fc].pcrel = op->reloc_flag; + if (fixups->fix[fixups->fc].reloc == BFD_RELOC_D30V_9_PCREL) + fixups->fix[fixups->fc].pcrel = RELOC_PCREL; + else + fixups->fix[fixups->fc].pcrel = op->reloc_flag; (fixups->fc)++; } @@ -520,7 +536,8 @@ build_insn (opcode, opers) as_bad("operand out of range: %d",number); if (bits < 31) number &= 0x7FFFFFFF >> (31 - bits); - + if (flags & OPERAND_SHIFT) + number >>= 3; if (bits == 32) { /* it's a LONG instruction */ @@ -723,21 +740,34 @@ parallel_ok (op1, insn1, op2, insn2, exec_type) unsigned long insn1, insn2; int exec_type; { - int i, j, flags, mask, shift, regno, bits; + int i, j, shift, regno, bits, ecc; + unsigned long flags, mask, flags_set1, flags_set2, flags_used1, flags_used2; unsigned long ins, mod_reg[2][3], used_reg[2][3]; struct d30v_format *f; struct d30v_opcode *op; + int reverse_p; /* section 4.3: both instructions must not be IU or MU only */ if ((op1->op->unit == IU && op2->op->unit == IU) || (op1->op->unit == MU && op2->op->unit == MU)) return 0; - /* - [0] r0-r31 - [1] r32-r63 - [2] a0, a1 - */ + /* first instruction must not be a jump to safely optimize */ + if (op1->op->flags_used & (FLAG_JMP | FLAG_JSR)) + return 0; + + /* If one instruction is /TX or /XT and the other is /FX or /XF respectively, + then it is safe to allow the two to be done as parallel ops, since only + one will ever be executed at a time. */ + if ((op1->ecc == ECC_TX && op2->ecc == ECC_FX) + || (op1->ecc == ECC_FX && op2->ecc == ECC_TX) + || (op1->ecc == ECC_XT && op2->ecc == ECC_XF) + || (op1->ecc == ECC_XF && op2->ecc == ECC_XT)) + return 1; + + /* [0] r0-r31 + [1] r32-r63 + [2] a0, a1, flag registers */ for (j = 0; j < 2; j++) { @@ -745,18 +775,44 @@ parallel_ok (op1, insn1, op2, insn2, exec_type) { f = op1->form; op = op1->op; + ecc = op1->ecc; ins = insn1; } else { f = op2->form; op = op2->op; + ecc = op2->ecc; ins = insn2; } mod_reg[j][0] = mod_reg[j][1] = 0; - mod_reg[j][2] = op->flags_set; + mod_reg[j][2] = (op->flags_set & FLAG_ALL); used_reg[j][0] = used_reg[j][1] = 0; - used_reg[j][2] = op->flags_used; + used_reg[j][2] = (op->flags_used & FLAG_ALL); + + /* BSR/JSR always sets R62 */ + if (op->flags_used & FLAG_JSR) + mod_reg[j][1] = (1L << (62-32)); + + /* conditional execution affects the flags_used */ + switch (ecc) + { + case ECC_TX: + case ECC_FX: + used_reg[j][2] |= FLAG_0; + break; + + case ECC_XT: + case ECC_XF: + used_reg[j][2] |= FLAG_1; + break; + + case ECC_TT: + case ECC_TF: + used_reg[j][2] |= (FLAG_0 | FLAG_1); + break; + } + for (i = 0; f->operands[i]; i++) { flags = d30v_operand_table[f->operands[i]].flags; @@ -766,47 +822,134 @@ parallel_ok (op1, insn1, op2, insn2, exec_type) mask = 0xffffffff; else mask = 0x7FFFFFFF >> (31 - bits); - if (flags & OPERAND_REG) + + if ((flags & OPERAND_PLUS) || (flags & OPERAND_MINUS)) + { + /* this is a post-increment or post-decrement */ + /* the previous register needs to be marked as modified */ + + shift = 12 - d30v_operand_table[f->operands[i-1]].position; + regno = (ins >> shift) & 0x3f; + if (regno >= 32) + mod_reg[j][1] |= 1L << (regno - 32); + else + mod_reg[j][0] |= 1L << regno; + } + else if (flags & OPERAND_REG) { regno = (ins >> shift) & mask; - if (flags & OPERAND_DEST) + /* the memory write functions don't have a destination register */ + if ((flags & OPERAND_DEST) && !(op->flags_set & FLAG_MEM)) { + /* MODIFIED registers and flags */ if (flags & OPERAND_ACC) - mod_reg[j][2] = 1 << (regno+16); + { + if (regno == 0) + mod_reg[j][2] |= FLAG_A0; + else if (regno == 1) + mod_reg[j][2] |= FLAG_A1; + else + abort (); + } else if (flags & OPERAND_FLAG) - mod_reg[j][2] = 1 << regno; + mod_reg[j][2] |= 1L << regno; else if (!(flags & OPERAND_CONTROL)) { - if (regno >= 32) - mod_reg[j][1] = 1 << (regno - 32); + int r, z; + + /* need to check if there are two destination */ + /* registers, for example ld2w */ + if (flags & OPERAND_2REG) + z = 1; else - mod_reg[j][0] = 1 << regno; + z = 0; + + for (r = regno; r <= regno + z; r++) + { + if (r >= 32) + mod_reg[j][1] |= 1L << (r - 32); + else + mod_reg[j][0] |= 1L << r; + } } } else { + /* USED, but not modified registers and flags */ if (flags & OPERAND_ACC) - used_reg[j][2] = 1 << (regno+16); + { + if (regno == 0) + used_reg[j][2] |= FLAG_A0; + else if (regno == 1) + used_reg[j][2] |= FLAG_A1; + else + abort (); + } else if (flags & OPERAND_FLAG) - used_reg[j][2] = 1 << regno; + used_reg[j][2] |= 1L << regno; else if (!(flags & OPERAND_CONTROL)) { - if (regno >= 32) - used_reg[j][1] = 1 << (regno - 32); + int r, z; + + /* need to check if there are two source */ + /* registers, for example st2w */ + if (flags & OPERAND_2REG) + z = 1; else - used_reg[j][0] = 1 << regno; + z = 0; + + for (r = regno; r <= regno + z; r++) + { + if (r >= 32) + used_reg[j][1] |= 1L << (r - 32); + else + used_reg[j][0] |= 1L << r; + } } } } } } + flags_set1 = op1->op->flags_set; + flags_set2 = op2->op->flags_set; + flags_used1 = op1->op->flags_used; + flags_used2 = op2->op->flags_used; + + /* ST2W/ST4HB combined with ADDppp/SUBppp is illegal. */ + if (((flags_set1 & (FLAG_MEM | FLAG_2WORD)) == (FLAG_MEM | FLAG_2WORD) + && (flags_used2 & FLAG_ADDSUBppp) != 0) + || ((flags_set2 & (FLAG_MEM | FLAG_2WORD)) == (FLAG_MEM | FLAG_2WORD) + && (flags_used1 & FLAG_ADDSUBppp) != 0)) + return 0; + + /* Load instruction combined with half-word multiply is illegal. */ + if (((flags_used1 & FLAG_MEM) != 0 && (flags_used2 & FLAG_MUL16)) + || ((flags_used2 & FLAG_MEM) != 0 && (flags_used1 & FLAG_MUL16))) + return 0; + + /* Specifically allow add || add by removing carry, overflow bits dependency. + This is safe, even if an addc follows since the IU takes the argument in + the right container, and it writes its results last. + However, don't paralellize add followed by addc or sub followed by + subb. */ + + if (mod_reg[0][2] == FLAG_CVVA && mod_reg[1][2] == FLAG_CVVA + && used_reg[0][2] == 0 && used_reg[1][2] == 0 + && op1->op->unit == EITHER && op2->op->unit == EITHER) + { + mod_reg[0][2] = mod_reg[1][2] = 0; + } + for(j = 0; j < 3; j++) - if ((mod_reg[0][j] & mod_reg[1][j]) - || (mod_reg[0][j] & used_reg[1][j]) - || (mod_reg[1][j] & used_reg[0][j])) - return 0; - + { + /* If the second instruction depends on the first, we obviously + cannot parallelize. Note, the mod flag implies use, so + check that as well. */ + if ((mod_reg[0][j] & (mod_reg[1][j] | used_reg[1][j])) != 0) + return 0; + } + return 1; } @@ -833,6 +976,9 @@ md_assemble (str) static int etype=0; /* saved extype. used for multiline instructions */ char *str2; + if ( (prev_insn != -1) && prev_seg && ((prev_seg != now_seg) || (prev_subseg != now_subseg))) + d30v_cleanup(); + if (etype == 0) { /* look for the special multiple instruction separators */ @@ -864,6 +1010,8 @@ md_assemble (str) prev_insn = do_assemble (str, &prev_opcode); if (prev_insn == -1) as_fatal ("cannot assemble instruction "); + if (prev_opcode.form->form >= LONG) + as_fatal ("First opcode is long. Unable to mix instructions as specified."); fixups = fixups->next; str = str2 + 2; } @@ -896,10 +1044,7 @@ md_assemble (str) prev_insn = -1; return; } - - if ( (prev_insn != -1) && prev_seg && ((prev_seg != now_seg) || (prev_subseg != now_subseg))) - d30v_cleanup(); - + if ( (prev_insn != -1) && (write_2_short (&prev_opcode, (long)prev_insn, &opcode, (long)insn, extype, fixups) == 0)) { @@ -931,7 +1076,7 @@ do_assemble (str, opcode) unsigned char *op_start, *save; unsigned char *op_end; char name[20]; - int cmp_hack, nlen = 0; + int cmp_hack, nlen = 0, fsize = 0; expressionS myops[6]; long long insn; @@ -992,6 +1137,16 @@ do_assemble (str, opcode) for(i=1; *str && strncmp(*str,&name[p],2); i++, *str++) ; + /* cmpu only supports some condition codes */ + if (p == 4) + { + if (i < 3 || i > 6) + { + name[p+2]=0; + as_fatal ("cmpu doesn't support condition code %s",&name[p]); + } + } + if (!*str) { name[p+2]=0; @@ -1006,6 +1161,21 @@ do_assemble (str, opcode) /* printf("cmp_hack=%d\n",cmp_hack); */ + /* need to look for .s or .l */ + if (name[nlen-2] == '.') + { + switch (name[nlen-1]) + { + case 's': + fsize = FORCE_SHORT; + break; + case 'l': + fsize = FORCE_LONG; + default: + } + name[nlen-2] = 0; + } + /* find the first opcode with the proper name */ opcode->op = (struct d30v_opcode *)hash_find (d30v_hash, name); if (opcode->op == NULL) @@ -1013,7 +1183,7 @@ do_assemble (str, opcode) save = input_line_pointer; input_line_pointer = op_end; - while (!(opcode->form = find_format (opcode->op, myops, cmp_hack))) + while (!(opcode->form = find_format (opcode->op, myops, fsize, cmp_hack))) { opcode->op++; if (strcmp(opcode->op->name,name)) @@ -1031,9 +1201,10 @@ do_assemble (str, opcode) /* to choose the correct one. Returns NULL on error. */ static struct d30v_format * -find_format (opcode, myops, cmp_hack) +find_format (opcode, myops, fsize, cmp_hack) struct d30v_opcode *opcode; expressionS myops[]; + int fsize; int cmp_hack; { int numops, match, index, i=0, j, k; @@ -1045,6 +1216,12 @@ find_format (opcode, myops, cmp_hack) while (index = opcode->format[i++]) { + if ((fsize == FORCE_SHORT) && (index >= LONG)) + continue; + + if ((fsize == FORCE_LONG) && (index < LONG)) + continue; + fm = (struct d30v_format *)&d30v_format_table[index]; k = index; while (fm->form == index) @@ -1089,6 +1266,9 @@ find_format (opcode, myops, cmp_hack) if (X_op != O_constant && X_op != O_symbol) match = 0; } + else if ((fm->form < LONG) && (((fsize == FORCE_SHORT) && (X_op == O_symbol)) || + (fm->form == SHORT_D2 && j == 0))) + match = 1; /* This is the tricky part. Will the constant or symbol */ /* fit into the space in the current format? */ else if (X_op == O_constant) @@ -1097,7 +1277,8 @@ find_format (opcode, myops, cmp_hack) match = 0; } else if (X_op == O_symbol && S_IS_DEFINED(myops[j].X_add_symbol) && - (S_GET_SEGMENT(myops[j].X_add_symbol) == now_seg)) + (S_GET_SEGMENT(myops[j].X_add_symbol) == now_seg) && + opcode->reloc_flag == RELOC_PCREL) { /* if the symbol is defined, see if the value will fit */ /* into the form we're considering */ @@ -1107,11 +1288,8 @@ find_format (opcode, myops, cmp_hack) /* and adding our current offset */ for (value = 0, f = frchain_now->frch_root; f; f = f->fr_next) value += f->fr_fix + f->fr_offset; - if (opcode->reloc_flag == RELOC_PCREL) - value = S_GET_VALUE(myops[j].X_add_symbol) - value - - (obstack_next_free(&frchain_now->frch_obstack) - frag_now->fr_literal); - else - value = S_GET_VALUE(myops[j].X_add_symbol); + value = S_GET_VALUE(myops[j].X_add_symbol) - value - + (obstack_next_free(&frchain_now->frch_obstack) - frag_now->fr_literal); if (check_range (value, d30v_operand_table[fm->operands[j]].bits, flags)) match = 0; } @@ -1169,7 +1347,8 @@ md_pcrel_from_section (fixp, sec) fixS *fixp; segT sec; { - if (fixp->fx_addsy != (symbolS *)NULL && !S_IS_DEFINED (fixp->fx_addsy)) + if (fixp->fx_addsy != (symbolS *)NULL && (!S_IS_DEFINED (fixp->fx_addsy) || + (S_GET_SEGMENT (fixp->fx_addsy) != sec))) return 0; return fixp->fx_frag->fr_address + fixp->fx_where; } @@ -1191,18 +1370,16 @@ md_apply_fix3 (fixp, valuep, seg) value = *valuep; fixp->fx_done = 1; } - else if (!S_IS_DEFINED(fixp->fx_addsy)) - return 0; else if (fixp->fx_pcrel) { value = *valuep; - } + } else { value = fixp->fx_offset; if (fixp->fx_subsy != (symbolS *) NULL) { - if (S_GET_SEGMENT (fixp->fx_subsy) == absolute_section) + if (S_GET_SEGMENT (fixp->fx_subsy) == absolute_section) value -= S_GET_VALUE (fixp->fx_subsy); else { @@ -1221,26 +1398,53 @@ md_apply_fix3 (fixp, valuep, seg) switch (fixp->fx_r_type) { case BFD_RELOC_D30V_6: + check_size (value, 6, fixp->fx_file, fixp->fx_line); insn |= value & 0x3F; bfd_putb32 ((bfd_vma) insn, (unsigned char *) where); break; + case BFD_RELOC_D30V_9_PCREL: + if (fixp->fx_where & 0x7) + { + if (fixp->fx_done) + value += 4; + else + fixp->fx_r_type = BFD_RELOC_D30V_9_PCREL_R; + } + check_size (value, 9, fixp->fx_file, fixp->fx_line); + insn |= ((value >> 3) & 0x3F) << 12; + bfd_putb32 ((bfd_vma) insn, (unsigned char *) where); + break; case BFD_RELOC_D30V_15: + check_size (value, 15, fixp->fx_file, fixp->fx_line); insn |= (value >> 3) & 0xFFF; bfd_putb32 ((bfd_vma) insn, (unsigned char *) where); break; case BFD_RELOC_D30V_15_PCREL: - if ((long)fixp->fx_where & 0x7) - value += 4; + if (fixp->fx_where & 0x7) + { + if (fixp->fx_done) + value += 4; + else + fixp->fx_r_type = BFD_RELOC_D30V_15_PCREL_R; + } + check_size (value, 15, fixp->fx_file, fixp->fx_line); insn |= (value >> 3) & 0xFFF; bfd_putb32 ((bfd_vma) insn, (unsigned char *) where); break; case BFD_RELOC_D30V_21: + check_size (value, 21, fixp->fx_file, fixp->fx_line); insn |= (value >> 3) & 0x3FFFF; bfd_putb32 ((bfd_vma) insn, (unsigned char *) where); break; case BFD_RELOC_D30V_21_PCREL: - if ((long)fixp->fx_where & 0x7) - value += 4; + if (fixp->fx_where & 0x7) + { + if (fixp->fx_done) + value += 4; + else + fixp->fx_r_type = BFD_RELOC_D30V_21_PCREL_R; + } + check_size (value, 21, fixp->fx_file, fixp->fx_line); insn |= (value >> 3) & 0x3FFFF; bfd_putb32 ((bfd_vma) insn, (unsigned char *) where); break; @@ -1253,8 +1457,6 @@ md_apply_fix3 (fixp, valuep, seg) bfd_putb32 ((bfd_vma) insn2, (unsigned char *) where + 4); break; case BFD_RELOC_D30V_32_PCREL: - if ((long)fixp->fx_where & 0x7) - value += 4; insn2 = bfd_getb32 ((unsigned char *) where + 4); insn |= (value >> 26) & 0x3F; /* top 6 bits */ insn2 |= ((value & 0x03FC0000) << 2); /* next 8 bits */ @@ -1268,7 +1470,6 @@ md_apply_fix3 (fixp, valuep, seg) default: as_fatal ("line %d: unknown relocation type: 0x%x",fixp->fx_line,fixp->fx_r_type); } - fixp->fx_done = 1; return 0; } @@ -1308,3 +1509,43 @@ d30v_number_to_chars (buf, value, n) value >>= 8; } } + + +/* This function is called at the start of every line. */ +/* it checks to see if the first character is a '.' */ +/* which indicates the start of a pseudo-op. If it is, */ +/* then write out any unwritten instructions */ + +void +d30v_start_line() +{ + char *c = input_line_pointer; + + while(isspace(*c)) + c++; + + if (*c == '.') + d30v_cleanup(); +} + +static void +check_size (value, bits, file, line) + long value; + int bits; + char *file; + int line; +{ + int tmp, max; + + if (value < 0) + tmp = ~value; + else + tmp = value; + + max = (1 << (bits - 1)) - 1; + + if (tmp > max) + as_bad_where (file, line,"value too large to fit in %d bits",bits); + + return; +}