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Re: [Patch-86512]: Subnormal float support in armv7(with -msoft-float) for intrinsics


Hi Umesh,

Looking at your patch, this would break all results which need to be normalized.


Index: libgcc/config/arm/ieee754-df.S
===================================================================
--- libgcc/config/arm/ieee754-df.S	(revision 262850)
+++ libgcc/config/arm/ieee754-df.S	(working copy)
@@ -203,8 +203,11 @@
 #endif
 
 	@ Determine how to normalize the result.
+	@ if result is denormal i.e (exp)=0,then don't normalise the result,
 LSYM(Lad_p):
 	cmp	xh, #0x00100000
+	blt	LSYM(Lad_e)
+	cmp	xh, #0x00100000
 	bcc	LSYM(Lad_a)
 	cmp	xh, #0x00200000
 	bcc	LSYM(Lad_e)

It seems Lad_a doesn't correctly handle the case where the result is a denormal. For this case
the result is correct so nothing else needs to be done. This requires an explicit test that the
exponent is zero - other cases still need to be renormalized as usual. This code looks overly
complex so any change will require extensive testing of all the corner cases.

Wilco


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