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| author | Ian Lance Taylor <ian@airs.com> | 1996-09-19 21:55:10 +0000 |
|---|---|---|
| committer | Ian Lance Taylor <ian@airs.com> | 1996-09-19 21:55:10 +0000 |
| commit | 47c6ce6c2de14635d0d71d63e5dbea036084b6ec (patch) | |
| tree | f201912ca1444749e9912657ae431043e8ac0215 /sim/mips | |
| parent | cc5201d78c016dc38c3dfbbb22b1332b80f88589 (diff) | |
| download | gdb-47c6ce6c2de14635d0d71d63e5dbea036084b6ec.zip gdb-47c6ce6c2de14635d0d71d63e5dbea036084b6ec.tar.gz gdb-47c6ce6c2de14635d0d71d63e5dbea036084b6ec.tar.bz2 | |
* gencode.c (process_instructions): Correct shift count for 32
bit shift instructions. Correct sign extension for arithmetic
shifts to not shift the number of bits in the type.
Diffstat (limited to 'sim/mips')
| -rw-r--r-- | sim/mips/ChangeLog | 4 | ||||
| -rw-r--r-- | sim/mips/gencode.c | 9 |
2 files changed, 9 insertions, 4 deletions
diff --git a/sim/mips/ChangeLog b/sim/mips/ChangeLog index 3c0099f..aed2073 100644 --- a/sim/mips/ChangeLog +++ b/sim/mips/ChangeLog @@ -1,7 +1,9 @@ Thu Sep 19 15:34:17 1996 Ian Lance Taylor <ian@cygnus.com> * gencode.c (process_instructions): Correct handling of nor - instruction. + instruction. Correct shift count for 32 bit shift instructions. + Correct sign extension for arithmetic shifts to not shift the + number of bits in the type. Mon Sep 16 11:38:16 1996 James G. Smith <jsmith@cygnus.co.uk> diff --git a/sim/mips/gencode.c b/sim/mips/gencode.c index 0dda11c..33ade54 100644 --- a/sim/mips/gencode.c +++ b/sim/mips/gencode.c @@ -1134,7 +1134,7 @@ process_instructions(doarch,features) /* If HI32 specified, then shift range is 32..63 */ if (MIPS_DECODE[loop].flags & HI32) - printf(" op1 |= (1 << 6);\n"); + printf(" op1 |= (1 << 5);\n"); /* We do not need to perform pre-masking with 0xFFFFFFFF when dealing with 32bit shift lefts, since the sign-extension @@ -1144,9 +1144,12 @@ process_instructions(doarch,features) else printf(" GPR[destreg] = ((uword64)(op2%s) >> op1);\n",((bits == 32) ? " & 0xFFFFFFFF" : "")); - /* For ARITHMETIC shifts, we must duplicate the sign-bit */ + /* For ARITHMETIC shifts, we must duplicate the sign-bit. We + don't do this if op1 is zero, since it is not needed and + since that would cause an undefined shift of the number of + bits in the type. */ if (MIPS_DECODE[loop].flags & ARITHMETIC) - printf(" GPR[destreg] |= ((op2 & ((%s)1 << %d)) ? ((((%s)1 << (op1 + 1)) - 1) << (%d - op1)) : 0);\n",ltype,(bits - 1),ltype,(bits - 1)); + printf(" GPR[destreg] |= (op1 != 0 && (op2 & ((%s)1 << %d)) ? ((((%s)1 << op1) - 1) << (%d - op1)) : 0);\n",ltype,(bits - 1),ltype,bits); /* Ensure WORD values are sign-extended into 64bit registers */ if ((bits == 32) && (gprlen == 64)) |