compiler indepenedent sign-extended signed right shift macroes

git-svn: trunk@3126

ChangeLog

@@ -1,3 +1,8 @@
+Sun Jul  8 17:25:04 CEST 2007 (acab)
+------------------------------------
+  * misc: Implement compiler indepenedent sign-extended signed right shift
+  	  when needed - reported by Michal Spadlinski <gim913 * gmail.com>
+
 Sat Jul 07 10:52:00 CEST 2007 (edwin)
 ----------------------------------
   * libclamav/phishcheck.c: fix typo in regex

clamav-config.h.in

@@ -216,6 +216,9 @@
 /* have resolv.h */
 #undef HAVE_RESOLV_H
 
+/* Define signed right shift implementation */
+#undef HAVE_SAR
+
 /* Define to 1 if you have the `sendmsg' function. */
 #undef HAVE_SENDMSG
 

configure

@@ -25852,6 +25852,63 @@ cat >>confdefs.h <<_ACEOF
 _ACEOF
 
 
+{ echo "$as_me:$LINENO: checking if signed right shift is sign extended" >&5
+echo $ECHO_N "checking if signed right shift is sign extended... $ECHO_C" >&6; }
+if test "$cross_compiling" = yes; then
+  have_signed_rightshift_extended=no
+else
+  cat >conftest.$ac_ext <<_ACEOF
+/* confdefs.h.  */
+_ACEOF
+cat confdefs.h >>conftest.$ac_ext
+cat >>conftest.$ac_ext <<_ACEOF
+/* end confdefs.h.  */
+int main(void){int a=-1;int b=a>>1;return(a!=b);}
+_ACEOF
+rm -f conftest$ac_exeext
+if { (ac_try="$ac_link"
+case "(($ac_try" in
+  *\"* | *\`* | *\\*) ac_try_echo=\$ac_try;;
+  *) ac_try_echo=$ac_try;;
+esac
+eval "echo \"\$as_me:$LINENO: $ac_try_echo\"") >&5
+  (eval "$ac_link") 2>&5
+  ac_status=$?
+  echo "$as_me:$LINENO: \$? = $ac_status" >&5
+  (exit $ac_status); } && { ac_try='./conftest$ac_exeext'
+  { (case "(($ac_try" in
+  *\"* | *\`* | *\\*) ac_try_echo=\$ac_try;;
+  *) ac_try_echo=$ac_try;;
+esac
+eval "echo \"\$as_me:$LINENO: $ac_try_echo\"") >&5
+  (eval "$ac_try") 2>&5
+  ac_status=$?
+  echo "$as_me:$LINENO: \$? = $ac_status" >&5
+  (exit $ac_status); }; }; then
+  have_signed_rightshift_extended=yes
+else
+  echo "$as_me: program exited with status $ac_status" >&5
+echo "$as_me: failed program was:" >&5
+sed 's/^/| /' conftest.$ac_ext >&5
+
+( exit $ac_status )
+have_signed_rightshift_extended=no
+fi
+rm -f core *.core core.conftest.* gmon.out bb.out conftest$ac_exeext conftest.$ac_objext conftest.$ac_ext
+fi
+
+
+if test $have_signed_rightshift_extended = yes; then
+
+cat >>confdefs.h <<\_ACEOF
+#define HAVE_SAR 1
+_ACEOF
+
+fi
+{ echo "$as_me:$LINENO: result: $have_signed_rightshift_extended" >&5
+echo "${ECHO_T}$have_signed_rightshift_extended" >&6; };
+
+
 ac_config_files="$ac_config_files libclamav/Makefile clamscan/Makefile database/Makefile docs/Makefile clamd/Makefile clamdscan/Makefile clamav-milter/Makefile freshclam/Makefile sigtool/Makefile clamconf/Makefile etc/Makefile Makefile clamav-config libclamav.pc docs/man/clamav-milter.8 docs/man/clamconf.1 docs/man/clamd.8 docs/man/clamd.conf.5 docs/man/clamdscan.1 docs/man/clamscan.1 docs/man/freshclam.1 docs/man/freshclam.conf.5 docs/man/sigtool.1"
 
 cat >confcache <<\_ACEOF

configure.in

@@ -1059,6 +1059,18 @@ DEFAULT_FD_SETSIZE=256)
 AC_MSG_RESULT($DEFAULT_FD_SETSIZE)
 AC_DEFINE_UNQUOTED(DEFAULT_FD_SETSIZE, $DEFAULT_FD_SETSIZE, "default FD_SETSIZE value")
 
+dnl Check signed right shift implementation
+AC_MSG_CHECKING(if signed right shift is sign extended)
+AC_TRY_RUN([int main(void){int a=-1;int b=a>>1;return(a!=b);}],
+    [have_signed_rightshift_extended=yes],
+    [have_signed_rightshift_extended=no],
+    [have_signed_rightshift_extended=no])
+if test $have_signed_rightshift_extended = yes; then
+    AC_DEFINE(HAVE_SAR, 1, Define signed right shift implementation)
+fi
+AC_MSG_RESULT($have_signed_rightshift_extended);
+
+
 AC_OUTPUT([
 libclamav/Makefile
 clamscan/Makefile

libclamav/others.h

@@ -132,6 +132,14 @@ typedef struct {
 #define ROL(a,b) a = ( a << (b % (sizeof(a)<<3) ))  |  (a >> (  (sizeof(a)<<3)  -  (b % (sizeof(a)<<3 )) ) )
 #define ROR(a,b) a = ( a >> (b % (sizeof(a)<<3) ))  |  (a << (  (sizeof(a)<<3)  -  (b % (sizeof(a)<<3 )) ) )
 
+/* Implementation independent sign-extended signed right shift */
+#ifdef HAVE_SAR
+#define SRS(n,s) ((n)>>(s))
+#else
+#define SRS(n,s) (((n)>>(s)) ^ (1<<(sizeof(n)*8-1-s)) - (1<<(sizeof(n)*8-1-s)))
+#endif
+#define SAR(n,s) n = SRS(n,s)
+
 #ifndef	FALSE
 #define FALSE (0)
 #endif

libclamav/unsp.c

@@ -400,7 +400,7 @@ int getbit_from_table(uint16_t *intable, struct UNSP *read_struct) {
     read_struct->bitmap = nval;
     nval = *intable;
     sval = 0x800 - nval;
-    sval = ((int32_t)sval)>>5; /* signed */
+    sval = SRS((int32_t)sval,5); /* signed */
     sval += nval;
     *intable=sval;
     if (read_struct->bitmap<0x1000000) { /* unsigned */

libclamav/upack.c

@@ -543,7 +543,7 @@ int unupack399(char *bs, uint32_t bl, uint32_t init_eax, char *init_ebx, uint32_
 						return -1;
 					/* cdq, loc_edx = (loc_eax&0x80000000)?0xffffffff:0; */
 					loc_ecx = temp_ebp;
-					temp_ebp = (int32_t)loc_eax >> 31; /* thx, desp */
+					temp_ebp = SRS((int32_t)loc_eax, 31); /* thx, desp */
 					/* loc_483a00 */
 					do {
 						temp_ebp += temp_ebp;

libclamav/upx.c

@@ -394,7 +394,7 @@ int upx_inflate2d(char *src, uint32_t ssize, char *dst, uint32_t *dsize, uint32_
       if (!backbytes)
 	break;
       backsize = backbytes & 1;
-      backbytes>>=1;
+      SAR(backbytes,1);
       unp_offset = backbytes;
     } else {
       if ( (backsize = (uint32_t)doubleebx(src, &myebx, &scur, ssize)) == 0xffffffff )
@@ -474,7 +474,7 @@ int upx_inflate2e(char *src, uint32_t ssize, char *dst, uint32_t *dsize, uint32_
       if (!backbytes)
 	break;
       backsize = backbytes & 1; /* Using backsize to carry on the shifted out bit (UPX uses CF) */
-      backbytes>>=1;
+      SAR(backbytes,1);
       unp_offset = backbytes;
     } else {
       if ( (backsize = (uint32_t)doubleebx(src, &myebx, &scur, ssize)) == 0xffffffff )