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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>
Jay Foad 11 жил өмнө
parent
commit
244b478386

+ 2 - 0
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);
 

+ 2 - 0
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);