mipscop-1.c: Add nomips16 attributes.

2007-09-05  Sandra Loosemore  <sandra@codesourcery.com>
	    David Ung  <davidu@mips.com>
            Nigel Stephens <nigel@mips.com>

	gcc/testsuite/
	* gcc.c-torture/compile/mipscop-1.c: Add nomips16 attributes.
	* gcc.c-torture/compile/mipscop-2.c: Likewise.
	* gcc.c-torture/compile/mipscop-3.c: Likewise.
	* gcc.c-torture/compile/mipscop-4.c: Likewise.
	* gcc.dg/torture/mips-hilo-1.c: Likewise.
	* gcc.dg/torture/mips-hilo-2.c: Likewise.
	* gcc.dg/torture/pr19683-1.c: Likewise.
	* gcc.target/mips/madd-3.c: Likewise.
	* gcc.target/mips/maddu-3.c: Likewise.
	* gcc.target/mips/msub-3.c: Likewise.
	* gcc.target/mips/msubu-3.c: Likewise.
	* gcc.target/mips/asm-1.c: Likewise.
	* gcc.target/mips/branch-1.c: Likewise.
	* gcc.target/mips/ins-1.c: Likewise.
	* gcc.target/mips/near-far-3.c: Likewise.
	* gcc.target/mips/near-far-4.c: Likewise.
	* gcc.target/mips/smartmips-lwxs.c: Likewise.
	* gcc.target/mips/smartmips-ror-1.c: Likewise.
	* gcc.target/mips/smartmips-ror-2.c: Likewise.
	* gcc.target/mips/smartmips-ror-3.c: Likewise.
	* gcc.target/mips/smartmips-ror-4.c: Likewise.
	* gcc.target/mips/dspr2-MULT.c: Likewise.
	* gcc.target/mips/dspr2-MULTU.c: Likewise.
	* gcc.target/mips/mips32-dsp-run.c: Likewise.
	* gcc.target/mips/mips32-dspr2-type.c: Likewise.
	* gcc.target/mips/code-readable-1.c: Add mips16 attributes.
	* gcc.target/mips/code-readable-2.c: Likewise.
	* gcc.target/mips/code-readable-3.c: Likewise.

Co-Authored-By: David Ung <davidu@mips.com>
Co-Authored-By: Nigel Stephens <nigel@mips.com>

From-SVN: r128135

gcc/testsuite/ChangeLog

@@ -2,6 +2,39 @@
 	    David Ung  <davidu@mips.com>
             Nigel Stephens <nigel@mips.com>
 
+	* gcc.c-torture/compile/mipscop-1.c: Add nomips16 attributes.
+	* gcc.c-torture/compile/mipscop-2.c: Likewise.
+	* gcc.c-torture/compile/mipscop-3.c: Likewise.
+	* gcc.c-torture/compile/mipscop-4.c: Likewise.
+	* gcc.dg/torture/mips-hilo-1.c: Likewise.
+	* gcc.dg/torture/mips-hilo-2.c: Likewise.
+	* gcc.dg/torture/pr19683-1.c: Likewise.
+	* gcc.target/mips/madd-3.c: Likewise.
+	* gcc.target/mips/maddu-3.c: Likewise.
+	* gcc.target/mips/msub-3.c: Likewise.
+	* gcc.target/mips/msubu-3.c: Likewise.
+	* gcc.target/mips/asm-1.c: Likewise.
+	* gcc.target/mips/branch-1.c: Likewise.
+	* gcc.target/mips/ins-1.c: Likewise.
+	* gcc.target/mips/near-far-3.c: Likewise.
+	* gcc.target/mips/near-far-4.c: Likewise.
+	* gcc.target/mips/smartmips-lwxs.c: Likewise.
+	* gcc.target/mips/smartmips-ror-1.c: Likewise.
+	* gcc.target/mips/smartmips-ror-2.c: Likewise.
+	* gcc.target/mips/smartmips-ror-3.c: Likewise.
+	* gcc.target/mips/smartmips-ror-4.c: Likewise.
+	* gcc.target/mips/dspr2-MULT.c: Likewise.
+	* gcc.target/mips/dspr2-MULTU.c: Likewise.
+	* gcc.target/mips/mips32-dsp-run.c: Likewise.
+	* gcc.target/mips/mips32-dspr2-type.c: Likewise.
+	* gcc.target/mips/code-readable-1.c: Add mips16 attributes.
+	* gcc.target/mips/code-readable-2.c: Likewise.
+	* gcc.target/mips/code-readable-3.c: Likewise.
+
+2007-09-05  Sandra Loosemore  <sandra@codesourcery.com>
+	    David Ung  <davidu@mips.com>
+            Nigel Stephens <nigel@mips.com>
+
 	* gcc.target/mips/mips16-attributes.c: New.
 
 2007-09-05  Paul Thomas  <pault@gcc.gnu.org>

gcc/testsuite/gcc.c-torture/compile/mipscop-1.c

 /* { dg-do compile { target mips*-*-* } } */
 
-#ifndef __mips16
 register unsigned int cp0count asm ("$c0r1");
 
-int
+int __attribute__ ((nomips16))
 main (int argc, char *argv[])
 {
   unsigned int d;
@@ -11,4 +10,3 @@ main (int argc, char *argv[])
   d = cp0count + 3;
   printf ("%d\n", d);
 }
-#endif

gcc/testsuite/gcc.c-torture/compile/mipscop-2.c

 /* { dg-do compile { target mips*-*-* } } */
 
-#ifndef __mips16
 register unsigned int c3r1 asm ("$c3r1");
 
 extern unsigned int b, c;
 
-void
+void __attribute__ ((nomips16))
 foo ()
 {
   unsigned int a, d;
@@ -17,4 +16,3 @@ foo ()
   d = c3r1;
   printf ("%d\n", d);
 }
-#endif

gcc/testsuite/gcc.c-torture/compile/mipscop-3.c

 /* { dg-do compile { target mips*-*-* } } */
 
-#ifndef __mips16
 register unsigned int c3r1 asm ("$c3r1"), c3r2 asm ("$c3r2");
 
 extern unsigned int b, c;
 
-void
+void __attribute__ ((nomips16))
 foo ()
 {
   unsigned int a, d;
@@ -17,4 +16,3 @@ foo ()
   d = c3r1;
   printf ("%d\n", d);
 }
-#endif

gcc/testsuite/gcc.c-torture/compile/mipscop-4.c

 /* { dg-do compile { target mips*-*-* } } */
 
-#ifndef __mips16
 register unsigned long c3r1 asm ("$c3r1"), c3r2 asm ("$c3r2");
 
 extern unsigned long b, c;
 
-void
+void __attribute__ ((nomips16))
 foo ()
 {
   unsigned long a, d;
@@ -17,4 +16,4 @@ foo ()
   d = c3r1;
   printf ("%d\n", d);
 }
-#endif
+

gcc/testsuite/gcc.dg/torture/mips-hilo-1.c

@@ -6,10 +6,8 @@
 extern void abort (void);
 extern void exit (int);
 
-#if !defined(__mips16)
-
 #define DECLARE(TYPE)							\
-  TYPE __attribute__ ((noinline))					\
+  TYPE __attribute__ ((noinline)) __attribute__ ((nomips16))		\
   f1##TYPE (TYPE x1, TYPE x2, TYPE x3)					\
   {									\
     TYPE t1, t2;							\
@@ -19,7 +17,7 @@ extern void exit (int);
     return t1 + t2;							\
   }									\
 									\
-  TYPE __attribute__ ((noinline))					\
+  TYPE __attribute__ ((noinline)) __attribute__ ((nomips16))		\
   f2##TYPE (TYPE x1, TYPE x2, TYPE x3)					\
   {									\
     TYPE t1, t2;							\
@@ -73,6 +71,3 @@ main ()
 #endif
   exit (0);
 }
-#else
-int main () { exit (0); }
-#endif

gcc/testsuite/gcc.dg/torture/mips-hilo-2.c

@@ -5,10 +5,9 @@
 extern void abort (void);
 extern void exit (int);
 
-#if !defined(__mips16)
 unsigned int g;
 
-unsigned long long f (unsigned int x)
+unsigned __attribute__ ((nomips16)) long long f (unsigned int x)
 {
   union { unsigned long long ll; unsigned int parts[2]; } u;
 
@@ -17,7 +16,7 @@ unsigned long long f (unsigned int x)
   return u.ll;
 }
 
-int main ()
+int __attribute__ ((nomips16)) main ()
 {
   union { unsigned long long ll; unsigned int parts[2]; } u;
 
@@ -26,6 +25,3 @@ int main ()
     abort ();
   exit (0);
 }
-#else
-int main () { exit (0); }
-#endif

gcc/testsuite/gcc.dg/torture/pr19683-1.c

@@ -6,7 +6,6 @@
 extern void abort (void);
 extern void exit (int);
 
-#ifndef __mips16
 #define REPEAT10(X, Y)					\
   X(Y##0); X(Y##1); X(Y##2); X(Y##3); X(Y##4);		\
   X(Y##5); X(Y##6); X(Y##7); X(Y##8); X(Y##9)
@@ -17,7 +16,7 @@ extern void exit (int);
 
 union u { unsigned long long ll; unsigned int i[2]; };
 
-unsigned int
+unsigned int __attribute__ ((nomips16))
 foo (volatile unsigned int *ptr)
 {
   union u u;
@@ -30,7 +29,7 @@ foo (volatile unsigned int *ptr)
   return result;
 }
 
-int
+int __attribute__ ((nomips16))
 main (void)
 {
   unsigned int array[] = { 1000 * 1000 * 1000 };
@@ -41,10 +40,3 @@ main (void)
     abort ();
   exit (0);
 }
-#else
-int
-main (void)
-{
-  exit (0);
-}
-#endif

gcc/testsuite/gcc.target/mips/asm-1.c

 /* PR target/17565.  GCC used to put the asm into the delay slot
    of the call.  */
 /* { dg-do assemble } */
-/* { dg-mips-options "-O -mno-mips16" } */
-int foo (int n)
+/* { dg-mips-options "-O" } */
+
+#define NOMIPS16 __attribute__ ((nomips16)) 
+
+NOMIPS16 int foo (int n)
 {
   register int k asm ("$16") = n;
   if (k > 0)

gcc/testsuite/gcc.target/mips/branch-1.c

 /* We should implement these "if" statements using an "andi" instruction
    followed by a branch on zero.  */
-/* { dg-mips-options "-O2 -mno-mips16" } */
+/* { dg-mips-options "-O2" } */
+
+#define NOMIPS16 __attribute__ ((nomips16)) 
+
 void bar (void);
-void f1 (int x) { if (x & 4) bar (); }
-void f2 (int x) { if ((x >> 2) & 1) bar (); }
-void f3 (unsigned int x) { if (x & 0x10) bar (); }
-void f4 (unsigned int x) { if ((x >> 4) & 1) bar (); }
+NOMIPS16 void f1 (int x) { if (x & 4) bar (); }
+NOMIPS16 void f2 (int x) { if ((x >> 2) & 1) bar (); }
+NOMIPS16 void f3 (unsigned int x) { if (x & 0x10) bar (); }
+NOMIPS16 void f4 (unsigned int x) { if ((x >> 4) & 1) bar (); }
 /* { dg-final { scan-assembler "\tandi\t.*\tandi\t.*\tandi\t.*\tandi\t" } } */
 /* { dg-final { scan-assembler-not "\tsrl\t" } } */
 /* { dg-final { scan-assembler-not "\tsra\t" } } */

gcc/testsuite/gcc.target/mips/code-readable-1.c

-/* { dg-mips-options "-mips16 -mcode-readable=yes -mgp32" } */
+/* { dg-mips-options "-mcode-readable=yes -mgp32" } */
 
-int
+#define MIPS16 __attribute__ ((mips16)) 
+
+MIPS16 int 
 foo (int i)
 {
   switch (i)
@@ -18,7 +20,7 @@ foo (int i)
 
 extern int k[];
 
-int *
+MIPS16 int *
 bar (void)
 {
   return k;

gcc/testsuite/gcc.target/mips/code-readable-2.c

-/* { dg-mips-options "-mips16 -mcode-readable=pcrel -mgp32" } */
+/* { dg-mips-options "-mcode-readable=pcrel -mgp32" } */
 
-int
+#define MIPS16 __attribute__ ((mips16))
+
+MIPS16 int
 foo (int i)
 {
   switch (i)
@@ -18,7 +20,7 @@ foo (int i)
 
 extern int k[];
 
-int *
+MIPS16 int *
 bar (void)
 {
   return k;

gcc/testsuite/gcc.target/mips/code-readable-3.c

-/* { dg-mips-options "-mips16 -mcode-readable=no -mgp32" } */
+/* { dg-mips-options "-mcode-readable=no -mgp32" } */
 
-int
+#define MIPS16 __attribute__ ((mips16))
+
+MIPS16 int
 foo (int i)
 {
   switch (i)
@@ -18,7 +20,7 @@ foo (int i)
 
 extern int k[];
 
-int *
+MIPS16 int *
 bar (void)
 {
   return k;

gcc/testsuite/gcc.target/mips/dspr2-MULT.c

@@ -7,11 +7,13 @@
 /* { dg-final { scan-assembler "ac2" } } */
 /* { dg-final { scan-assembler "ac3" } } */
 
+#define NOMIPS16 __attribute__ ((nomips16)) 
+
 typedef long long a64;
 a64 a[4];
 int b[4], c[4];
 
-void test ()
+NOMIPS16 void test ()
 {
   a[0] = (a64) b[0] * c[0];
   a[1] = (a64) b[1] * c[1];

gcc/testsuite/gcc.target/mips/dspr2-MULTU.c

@@ -7,11 +7,13 @@
 /* { dg-final { scan-assembler "ac2" } } */
 /* { dg-final { scan-assembler "ac3" } } */
 
+#define NOMIPS16 __attribute__ ((nomips16)) 
+
 typedef long long a64;
 a64 a[4];
 unsigned int b[4], c[4];
 
-void test ()
+NOMIPS16 void test ()
 {
   a[0] = (a64) b[0] * c[0];
   a[1] = (a64) b[1] * c[1];

gcc/testsuite/gcc.target/mips/ins-1.c

 /* { dg-do compile } */
-/* { dg-mips-options "-O -march=mips32r2 -mno-mips16" } */
+/* { dg-mips-options "-O -march=mips32r2" } */
 /* { dg-final { scan-assembler "\tins\t" } } */
 
+#define NOMIPS16 __attribute__ ((nomips16)) 
+
 struct
 {
   unsigned int i : 2;
@@ -9,7 +11,7 @@ struct
   unsigned int k : 4;
 } s;
 
-void
+NOMIPS16 void
 foo (void)
 {
   s.j = 1;

gcc/testsuite/gcc.target/mips/madd-3.c

@@ -2,19 +2,21 @@
 /* { dg-mips-options "-O2 -mips32 -mgp32" } */
 /* { dg-final { scan-assembler-times "\tmadd\t" 3 } } */
 
-long long
+#define NOMIPS16 __attribute__ ((nomips16)) 
+
+NOMIPS16 long long
 f1 (int x, int y, long long z)
 {
   return (long long) x * y + z;
 }
 
-long long
+NOMIPS16 long long
 f2 (int x, int y, long long z)
 {
   return z + (long long) y * x;
 }
 
-long long
+NOMIPS16 long long
 f3 (int x, int y, long long z)
 {
   long long t = (long long) x * y;

gcc/testsuite/gcc.target/mips/maddu-3.c

@@ -2,22 +2,24 @@
 /* { dg-mips-options "-O2 -mips32 -mgp32" } */
 /* { dg-final { scan-assembler-times "\tmaddu\t" 3 } } */
 
+#define NOMIPS16 __attribute__ ((nomips16)) 
+
 typedef unsigned int ui;
 typedef unsigned long long ull;
 
-ull
+NOMIPS16 ull
 f1 (ui x, ui y, ull z)
 {
   return (ull) x * y + z;
 }
 
-ull
+NOMIPS16 ull
 f2 (ui x, ui y, ull z)
 {
   return z + (ull) y * x;
 }
 
-ull
+NOMIPS16 ull
 f3 (ui x, ui y, ull z)
 {
   ull t = (ull) x * y;

gcc/testsuite/gcc.target/mips/mips32-dsp-run.c

@@ -2,6 +2,8 @@
 /* { dg-do run { target mipsisa32r2*-*-* } } */
 /* { dg-mips-options "-march=mips32r2 -mdsp -O2" } */
 
+#define NOMIPS16 __attribute__ ((nomips16)) 
+
 #include <stdlib.h>
 #include <stdio.h>
 
@@ -12,7 +14,7 @@ typedef int q31;
 typedef int i32;
 typedef long long a64;
 
-void test_MIPS_DSP (void);
+NOMIPS16 void test_MIPS_DSP (void);
 
 char array[100];
 int little_endian;
@@ -33,27 +35,27 @@ int main ()
   exit (0);
 }
 
-v2q15 add_v2q15 (v2q15 a, v2q15 b)
+NOMIPS16 v2q15 add_v2q15 (v2q15 a, v2q15 b)
 {
   return __builtin_mips_addq_ph (a, b);
 }
 
-v4i8 add_v4i8 (v4i8 a, v4i8 b)
+NOMIPS16 v4i8 add_v4i8 (v4i8 a, v4i8 b)
 {
   return __builtin_mips_addu_qb (a, b);
 }
 
-v2q15 sub_v2q15 (v2q15 a, v2q15 b)
+NOMIPS16 v2q15 sub_v2q15 (v2q15 a, v2q15 b)
 {
   return __builtin_mips_subq_ph (a, b);
 }
 
-v4i8 sub_v4i8 (v4i8 a, v4i8 b)
+NOMIPS16 v4i8 sub_v4i8 (v4i8 a, v4i8 b)
 {
   return __builtin_mips_subu_qb (a, b);
 }
 
-void test_MIPS_DSP ()
+NOMIPS16 void test_MIPS_DSP ()
 {
   v4i8 v4i8_a,v4i8_b,v4i8_c,v4i8_r,v4i8_s;
   v2q15 v2q15_a,v2q15_b,v2q15_c,v2q15_r,v2q15_s;

gcc/testsuite/gcc.target/mips/mips32-dspr2-type.c

@@ -3,9 +3,11 @@
 /* { dg-mips-options "-march=mips32r2 -mdspr2" } */
 /* { dg-final { scan-assembler "\tmul.ph\t" } } */
 
+#define NOMIPS16 __attribute__ ((nomips16))
+
 typedef short v2hi __attribute__ ((vector_size(4)));
 
-v2hi mul_v2hi (v2hi a, v2hi b)
+NOMIPS16 v2hi mul_v2hi (v2hi a, v2hi b)
 {
   return a * b;
 }

gcc/testsuite/gcc.target/mips/msub-3.c

@@ -2,13 +2,15 @@
 /* { dg-mips-options "-O2 -mips32 -mgp32" } */
 /* { dg-final { scan-assembler-times "\tmsub\t" 2 } } */
 
-long long
+#define NOMIPS16 __attribute__ ((nomips16))
+
+NOMIPS16 long long
 f1 (int x, int y, long long z)
 {
   return z - (long long) y * x;
 }
 
-long long
+NOMIPS16 long long
 f2 (int x, int y, long long z)
 {
   long long t = (long long) x * y;

gcc/testsuite/gcc.target/mips/msubu-3.c

@@ -2,16 +2,18 @@
 /* { dg-mips-options "-O2 -mips32 -mgp32" } */
 /* { dg-final { scan-assembler-times "\tmsubu\t" 2 } } */
 
+#define NOMIPS16 __attribute__ ((nomips16)) 
+
 typedef unsigned int ui;
 typedef unsigned long long ull;
 
-ull
+NOMIPS16 ull
 f1 (ui x, ui y, ull z)
 {
   return z - (ull) y * x;
 }
 
-ull
+NOMIPS16 ull
 f2 (ui x, ui y, ull z)
 {
   ull t = (ull) x * y;

gcc/testsuite/gcc.target/mips/near-far-3.c

 /* { dg-do compile } */
-/* { dg-mips-options "-mlong-calls -O2 -mno-mips16" } */
+/* { dg-mips-options "-mlong-calls -O2" } */
 /* { dg-require-effective-target nonpic } */
 
-extern int long_call_func () __attribute__((long_call));
-extern int far_func () __attribute__((far));
-extern int near_func () __attribute__((near));
-extern int normal_func ();
+#define NOMIPS16 __attribute__ ((nomips16)) 
 
-int test1 () { return long_call_func (); }
-int test2 () { return far_func (); }
-int test3 () { return near_func (); }
-int test4 () { return normal_func (); }
+NOMIPS16 extern int long_call_func () __attribute__((long_call));
+NOMIPS16 extern int far_func () __attribute__((far));
+NOMIPS16 extern int near_func () __attribute__((near));
+NOMIPS16 extern int normal_func ();
+
+NOMIPS16 int test1 () { return long_call_func (); }
+NOMIPS16 int test2 () { return far_func (); }
+NOMIPS16 int test3 () { return near_func (); }
+NOMIPS16 int test4 () { return normal_func (); }
 
 /* { dg-final { scan-assembler-not "\tj\tlong_call_func\n" } } */
 /* { dg-final { scan-assembler-not "\tj\tfar_func\n" } } */

gcc/testsuite/gcc.target/mips/near-far-4.c

 /* { dg-do compile } */
-/* { dg-mips-options "-mno-long-calls -O2 -mno-mips16" } */
+/* { dg-mips-options "-mno-long-calls -O2" } */
 /* { dg-require-effective-target nonpic } */
 
-extern int long_call_func () __attribute__((long_call));
-extern int far_func () __attribute__((far));
-extern int near_func () __attribute__((near));
-extern int normal_func ();
+#define NOMIPS16 __attribute__ ((nomips16)) 
 
-int test1 () { return long_call_func (); }
-int test2 () { return far_func (); }
-int test3 () { return near_func (); }
-int test4 () { return normal_func (); }
+NOMIPS16 extern int long_call_func () __attribute__((long_call));
+NOMIPS16 extern int far_func () __attribute__((far));
+NOMIPS16 extern int near_func () __attribute__((near));
+NOMIPS16 extern int normal_func ();
+
+NOMIPS16 int test1 () { return long_call_func (); }
+NOMIPS16 int test2 () { return far_func (); }
+NOMIPS16 int test3 () { return near_func (); }
+NOMIPS16 int test4 () { return normal_func (); }
 
 /* { dg-final { scan-assembler-not "\tj\tlong_call_func\n" } } */
 /* { dg-final { scan-assembler-not "\tj\tfar_func\n" } } */

gcc/testsuite/gcc.target/mips/smartmips-lwxs.c

 /* { dg-do compile } */
-/* { dg-mips-options "-O -msmartmips -mno-mips16" } */
+/* { dg-mips-options "-O -msmartmips" } */
 
-int scaled_indexed_word_load (int a[], int b)
+#define NOMIPS16 __attribute__ ((nomips16)) 
+
+NOMIPS16 int scaled_indexed_word_load (int a[], int b)
 {
   return a[b];
 }

gcc/testsuite/gcc.target/mips/smartmips-ror-1.c

 /* { dg-do compile } */
-/* { dg-mips-options "-O -msmartmips -mno-mips16" } */
+/* { dg-mips-options "-O -msmartmips" } */
 
-int rotate_left (unsigned a, unsigned s)
+#define NOMIPS16 __attribute__ ((nomips16)) 
+
+NOMIPS16 int rotate_left (unsigned a, unsigned s)
 {
   return (a << s) | (a >> (32 - s));
 }

gcc/testsuite/gcc.target/mips/smartmips-ror-2.c

 /* { dg-do compile } */
-/* { dg-mips-options "-O -msmartmips -mno-mips16" } */
+/* { dg-mips-options "-O -msmartmips" } */
 
-int rotate_right (unsigned a, unsigned s)
+#define NOMIPS16 __attribute__ ((nomips16)) 
+
+NOMIPS16 int rotate_right (unsigned a, unsigned s)
 {
   return (a >> s) | (a << (32 - s));
 }

gcc/testsuite/gcc.target/mips/smartmips-ror-3.c

 /* { dg-do compile } */
-/* { dg-mips-options "-O -msmartmips -mno-mips16" } */
+/* { dg-mips-options "-O -msmartmips" } */
+
+#define NOMIPS16 __attribute__ ((nomips16)) 
 
 #define S 13
 
-int rotate_left_constant (unsigned a)
+NOMIPS16 int rotate_left_constant (unsigned a)
 {
   return (a << S) | (a >> (32 - S));
 }

gcc/testsuite/gcc.target/mips/smartmips-ror-4.c

 /* { dg-do compile } */
-/* { dg-mips-options "-O -msmartmips -mno-mips16" } */
+/* { dg-mips-options "-O -msmartmips" } */
+
+#define NOMIPS16 __attribute__ ((nomips16)) 
 
 #define S 13
 
-int rotate_right_constant (unsigned a)
+NOMIPS16 int rotate_right_constant (unsigned a)
 {
   return (a >> S) | (a << (32 - S));
 }