ARM: 8026/1: Fix emulation of multiply accumulate instructions

The emulation for single and double precision multiply accumulate
instructions correctly normalised any denormal values in the operand
registers, but failed to normalise the destination (accumulator)
register.

This fixes https://bugzilla.kernel.org/show_bug.cgi?id=70501

Signed-off-by: Jay Foad <jay.foad@gmail.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

diff --git a/arch/arm/vfp/vfpdouble.c b/arch/arm/vfp/vfpdouble.c
index 6cac43bd1d86c63638993bafa8ba989fea52e91f..423f56dd40283c3f7615a5aec0c1d5422313d61a 100644 (file)
--- a/arch/arm/vfp/vfpdouble.c
+++ b/arch/arm/vfp/vfpdouble.c
@@ -866,6 +866,8 @@ vfp_double_multiply_accumulate(int dd, int dn, int dm, u32 fpscr, u32 negate, ch
                vdp.sign = vfp_sign_negate(vdp.sign);
 
        vfp_double_unpack(&vdn, vfp_get_double(dd));
+       if (vdn.exponent == 0 && vdn.significand)
+               vfp_double_normalise_denormal(&vdn);
        if (negate & NEG_SUBTRACT)
                vdn.sign = vfp_sign_negate(vdn.sign);
 

diff --git a/arch/arm/vfp/vfpsingle.c b/arch/arm/vfp/vfpsingle.c
index b252631b406bd22bcbe040ede3d3f4dfbea8e987..4f96c1617aaec257a68496464aacbafe1f8d7ab8 100644 (file)
--- a/arch/arm/vfp/vfpsingle.c
+++ b/arch/arm/vfp/vfpsingle.c
@@ -915,6 +915,8 @@ vfp_single_multiply_accumulate(int sd, int sn, s32 m, u32 fpscr, u32 negate, cha
        v = vfp_get_float(sd);
        pr_debug("VFP: s%u = %08x\n", sd, v);
        vfp_single_unpack(&vsn, v);
+       if (vsn.exponent == 0 && vsn.significand)
+               vfp_single_normalise_denormal(&vsn);
        if (negate & NEG_SUBTRACT)
                vsn.sign = vfp_sign_negate(vsn.sign);