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for DIV: check for div by zero and int overflow

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This commit is contained in:
Gavin Romig-Koch 1997-04-21 21:26:17 +00:00
parent e4bb902716
commit d654ba0acf
2 changed files with 44 additions and 15 deletions
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6
sim/mips/ChangeLog
View File

@ -1,3 +1,9 @@
Mon Apr 21 17:16:13 1997 Gavin Koch <gavin@cygnus.com>
* gencode.c (build_instruction): DIV instructions: check
for division by zero and integer overflow before using
host's division operation.
Thu Apr 17 03:18:14 1997 Doug Evans <dje@canuck.cygnus.com>
* Makefile.in (SIM_OBJS): Add sim-load.o.

53
sim/mips/gencode.c
View File

@ -2241,30 +2241,53 @@ build_instruction (doisa, features, mips16, insn)
case DIV:
{
int boolU = (insn->flags & UNSIGNED);
int pipe1 = (insn->flags & PIPE1);
char* pipe = (insn->flags & PIPE1) ? "1" : "";
if (features & FEATURE_WARN_LOHI) {
printf(" CHECKHILO(\"Division\");\n");
printf(" CHECKHILO(\"Division\");\n");
}
printf(" {\n");
if (GETDATASIZEINSN(insn) == DOUBLEWORD) {
printf(" LO%s = ((%sword64)op1 / (%sword64)op2);\n",
(pipe1 ? "1" : ""),
(boolU ? "u" : ""),(boolU ? "u" : ""));
printf(" HI%s = ((%sword64)op1 %c (%sword64)op2);\n",
(pipe1 ? "1" : ""),
(boolU ? "u" : ""),'%',(boolU ? "u" : ""));
printf(" %sword64 d1 = op1;\n", (boolU ? "u" : ""));
printf(" %sword64 d2 = op2;\n", (boolU ? "u" : ""));
printf(" if (d2 == 0)\n");
printf(" {\n");
printf(" LO%s = 0x8000000000000000LL;\n", pipe);
printf(" HI%s = 0;\n", pipe);
printf(" }\n");
printf(" else if (d2 == -1 && d1 == 0x8000000000000000LL)\n");
printf(" {\n");
printf(" LO%s = 0x8000000000000000LL;\n", pipe);
printf(" HI%s = 0;\n", pipe);
printf(" }\n");
printf(" else\n");
printf(" {\n");
printf(" LO%s = (d1 / d2);\n", pipe);
printf(" HI%s = (d1 %% d2);\n", pipe);
printf(" }\n");
} else {
printf(" LO%s = SIGNEXTEND(((%sint)op1 / (%sint)op2),32);\n",
(pipe1 ? "1" : ""),
(boolU ? "unsigned " : ""),(boolU ? "unsigned " : ""));
printf(" HI%s = SIGNEXTEND(((%sint)op1 %c (%sint)op2),32);\n",
(pipe1 ? "1" : ""),
(boolU ? "unsigned " : ""),'%',(boolU ? "unsigned " : ""));
printf(" %sint d1 = op1;\n", (boolU ? "unsigned " : ""));
printf(" %sint d2 = op2;\n", (boolU ? "unsigned " : ""));
printf(" if (d2 == 0)\n");
printf(" {\n");
printf(" LO%s = SIGNEXTEND(0x80000000,32);\n",pipe);
printf(" HI%s = SIGNEXTEND(0,32);\n", pipe);
printf(" }\n");
printf(" else if (d2 == -1 && d1 == 0x80000000)\n");
printf(" {\n");
printf(" LO%s = SIGNEXTEND(0x80000000,32);\n",pipe);
printf(" HI%s = SIGNEXTEND(0,32);\n", pipe);
printf(" }\n");
printf(" else\n");
printf(" {\n");
printf(" LO%s = SIGNEXTEND((d1 / d2),32);\n", pipe);
printf(" HI%s = SIGNEXTEND((d1 %% d2),32);\n", pipe);
printf(" }\n");
}
printf(" }\n");
}
break ;
break ;
case SHIFT:
{