[dotgnu-pnet-commits] libjit ChangeLog jit/jit-rules-x86.ins

[Klaus Treichel]

CVSROOT:        /cvsroot/dotgnu-pnet
Module name:    libjit
Changes by:     Klaus Treichel <ktreichel>      08/03/29 18:45:25

Modified files:
        .              : ChangeLog 
        jit            : jit-rules-x86.ins 

Log message:
        Fix signed division of a negative value by a positive power of two on 
x86.

CVSWeb URLs:
http://cvs.savannah.gnu.org/viewcvs/libjit/ChangeLog?cvsroot=dotgnu-pnet&r1=1.355&r2=1.356
http://cvs.savannah.gnu.org/viewcvs/libjit/jit/jit-rules-x86.ins?cvsroot=dotgnu-pnet&r1=1.33&r2=1.34

Patches:
Index: ChangeLog
===================================================================
RCS file: /cvsroot/dotgnu-pnet/libjit/ChangeLog,v
retrieving revision 1.355
retrieving revision 1.356
diff -u -b -r1.355 -r1.356
--- ChangeLog   29 Mar 2008 15:01:36 -0000      1.355
+++ ChangeLog   29 Mar 2008 18:45:24 -0000      1.356
@@ -1,3 +1,8 @@
+2008-03-29  Klaus treichel  <address@hidden>
+
+       * jit/jit-rules-x86.ins: Fix signed division of negative values by a
+       constant positive power of two.
+
 2008-03-29  Klaus Treichel  <address@hidden>
 
        * jit/jit-apply.c, tools/gen-apply.c: changes to apply needed for

Index: jit/jit-rules-x86.ins
===================================================================
RCS file: /cvsroot/dotgnu-pnet/libjit/jit/jit-rules-x86.ins,v
retrieving revision 1.33
retrieving revision 1.34
diff -u -b -r1.33 -r1.34
--- jit/jit-rules-x86.ins       24 Jan 2008 20:12:53 -0000      1.33
+++ jit/jit-rules-x86.ins       29 Mar 2008 18:45:25 -0000      1.34
@@ -584,13 +584,26 @@
                x86_patch(patch, inst);
                x86_neg_reg(inst, $1);
        }
-       [reg, imm, if("(((jit_nuint)$2) & (((jit_nuint)$2) - 1)) == 0")] -> {
+       [reg, imm, scratch reg, if("$2 == 2")] -> {
+               x86_mov_reg_reg(inst, $3, $1, 4);
+               x86_shift_reg_imm(inst, X86_SHR, $3, 0x1f);
+               x86_alu_reg_reg(inst, X86_ADD, $1, $3);
+               x86_shift_reg_imm(inst, X86_SAR, $1, 1);
+       }
+       [reg, imm, scratch reg, if("($2 > 0) && (((jit_nuint)$2) & 
(((jit_nuint)$2) - 1)) == 0")] -> {
                /* x & (x - 1) is equal to zero if x is a power of 2  */
-               jit_nuint shift, value = $2 >> 1;
+               /* This code is generated by gcc for pentium. */
+               /* We use this code because cmov is not available on all i386 
cpus */
+               jit_nuint shift, temp, value = $2 >> 1;
                for(shift = 0; value; value >>= 1)
                {
                    ++shift;
                }
+               temp = 32 - shift;
+               x86_mov_reg_reg(inst, $3, $1, 4);
+               x86_shift_reg_imm(inst, X86_SAR, $3, 0x1f);
+               x86_shift_reg_imm(inst, X86_SHR, $3, temp);
+               x86_alu_reg_reg(inst, X86_ADD, $1, $3);
                x86_shift_reg_imm(inst, X86_SAR, $1, shift);
        }
        [reg("eax"), imm, scratch reg, scratch reg("edx")] -> {