bn/bn_exp.c: harmonize.

(cherry picked from commit cbce8c4644fa8dfa72e62a2aa921a74eee6d62c9)

diff --git a/crypto/bn/bn_exp.c b/crypto/bn/bn_exp.c
index fa10ea1773dccbc0bb12b748505a8c4aca46728f..bd26740c46da3c345dd8fc8649476fbb150be017 100644 (file)
--- a/crypto/bn/bn_exp.c
+++ b/crypto/bn/bn_exp.c
@@ -127,9 +127,11 @@
 # include <alloca.h>
 #endif
 
+#undef SPARC_T4_MONT
 #if defined(OPENSSL_BN_ASM_MONT) && (defined(__sparc__) || defined(__sparc))
 # include "sparc_arch.h"
 extern unsigned int OPENSSL_sparcv9cap_P[];
+# define SPARC_T4_MONT
 #endif
 
 /* maximum precomputation table size for *variable* sliding windows */
@@ -475,14 +477,18 @@ int BN_mod_exp_mont(BIGNUM *rr, const BIGNUM *a, const BIGNUM *p,
        wend=0;         /* The bottom bit of the window */
 
 #if 1  /* by Shay Gueron's suggestion */
-       j = mont->N.top;        /* borrow j */
-       if (bn_wexpand(r,j) == NULL) goto err;
-       r->d[0] = (0-m->d[0])&BN_MASK2;         /* 2^(top*BN_BITS2) - m */
-       for(i=1;i<j;i++) r->d[i] = (~m->d[i])&BN_MASK2;
-       r->top = j;
-#else
-       if (!BN_to_montgomery(r,BN_value_one(),mont,ctx)) goto err;
+       j = m->top;     /* borrow j */
+       if (m->d[j-1] & (((BN_ULONG)1)<<(BN_BITS2-1)))
+               {
+               if (bn_wexpand(r,j) == NULL) goto err;
+               /* 2^(top*BN_BITS2) - m */
+               r->d[0] = (0-m->d[0])&BN_MASK2;
+               for(i=1;i<j;i++) r->d[i] = (~m->d[i])&BN_MASK2;
+               r->top = j;
+               }
+       else
 #endif
+       if (!BN_to_montgomery(r,BN_value_one(),mont,ctx)) goto err;
        for (;;)
                {
                if (BN_is_bit_set(p,wstart) == 0)
@@ -534,7 +540,7 @@ int BN_mod_exp_mont(BIGNUM *rr, const BIGNUM *a, const BIGNUM *p,
                start=0;
                if (wstart < 0) break;
                }
-#if defined(OPENSSL_BN_ASM_MONT) && (defined(__sparc__) || defined(__sparc))
+#if defined(SPARC_T4_MONT)
        if (OPENSSL_sparcv9cap_P[0]&(SPARCV9_VIS3|SPARCV9_PREFER_FPU))
                {
                j = mont->N.top;        /* borrow j */
@@ -554,7 +560,7 @@ err:
        return(ret);
        }
 
-#if defined(OPENSSL_BN_ASM_MONT) && (defined(__sparc__) || defined(__sparc))
+#if defined(SPARC_T4_MONT)
 static BN_ULONG bn_get_bits(const BIGNUM *a, int bitpos)
        {
        BN_ULONG ret=0;
@@ -635,7 +641,7 @@ int BN_mod_exp_mont_consttime(BIGNUM *rr, const BIGNUM *a, const BIGNUM *p,
        int powerbufLen = 0;
        unsigned char *powerbuf=NULL;
        BIGNUM tmp, am;
-#if defined(OPENSSL_BN_ASM_MONT) && (defined(__sparc__) || defined(__sparc))
+#if defined(SPARC_T4_MONT)
        unsigned int t4=0;
 #endif
 
@@ -672,7 +678,7 @@ int BN_mod_exp_mont_consttime(BIGNUM *rr, const BIGNUM *a, const BIGNUM *p,
 
        /* Get the window size to use with size of p. */
        window = BN_window_bits_for_ctime_exponent_size(bits);
-#if defined(OPENSSL_BN_ASM_MONT) && (defined(__sparc__) || defined(__sparc))
+#if defined(SPARC_T4_MONT)
        if (window>=5 && (top&15)==0 && top<=64 &&
            (OPENSSL_sparcv9cap_P[1]&(CFR_MONTMUL|CFR_MONTSQR))==
                                     (CFR_MONTMUL|CFR_MONTSQR) &&
@@ -717,13 +723,16 @@ int BN_mod_exp_mont_consttime(BIGNUM *rr, const BIGNUM *a, const BIGNUM *p,
 
        /* prepare a^0 in Montgomery domain */
 #if 1  /* by Shay Gueron's suggestion */
-       tmp.d[0] = (0-m->d[0])&BN_MASK2;        /* 2^(top*BN_BITS2) - m */
-       for (i=1;i<top;i++)
-               tmp.d[i] = (~m->d[i])&BN_MASK2;
-       tmp.top = top;
-#else
-       if (!BN_to_montgomery(&tmp,BN_value_one(),mont,ctx))    goto err;
+       if (m->d[top-1] & (((BN_ULONG)1)<<(BN_BITS2-1)))
+               {
+               /* 2^(top*BN_BITS2) - m */
+               tmp.d[0] = (0-m->d[0])&BN_MASK2;
+               for (i=1;i<top;i++) tmp.d[i] = (~m->d[i])&BN_MASK2;
+               tmp.top = top;
+               }
+       else
 #endif
+       if (!BN_to_montgomery(&tmp,BN_value_one(),mont,ctx))    goto err;
 
        /* prepare a^1 in Montgomery domain */
        if (a->neg || BN_ucmp(a,m) >= 0)
@@ -733,7 +742,7 @@ int BN_mod_exp_mont_consttime(BIGNUM *rr, const BIGNUM *a, const BIGNUM *p,
                }
        else    if (!BN_to_montgomery(&am,a,mont,ctx))          goto err;
 
-#if defined(OPENSSL_BN_ASM_MONT) && (defined(__sparc__) || defined(__sparc))
+#if defined(SPARC_T4_MONT)
     if (t4)
        {
        typedef int (*bn_pwr5_mont_f)(BN_ULONG *tp,const BN_ULONG *np,
@@ -991,7 +1000,7 @@ int BN_mod_exp_mont_consttime(BIGNUM *rr, const BIGNUM *a, const BIGNUM *p,
        }
 
        /* Convert the final result from montgomery to standard format */
-#if defined(OPENSSL_BN_ASM_MONT) && (defined(__sparc__) || defined(__sparc))
+#if defined(SPARC_T4_MONT)
        if (OPENSSL_sparcv9cap_P[0]&(SPARCV9_VIS3|SPARCV9_PREFER_FPU))
                {
                am.d[0] = 1;    /* borrow am */