From: Mark Wooding <mdw@distorted.org.uk>
Date: Thu, 7 Nov 2019 01:51:37 +0000 (+0000)
Subject: math/mpx-mul4-amd64-sse2.S: Save a spill by better register allocation.
X-Git-Tag: 2.6.0~14
X-Git-Url: https://git.distorted.org.uk/~mdw/catacomb/commitdiff_plain/f79c8756d054b2979f79d8277affb988c4f39c49

math/mpx-mul4-amd64-sse2.S: Save a spill by better register allocation.

The Windows code doesn't need to spill r12, because we don't need the
`mi' register after we've loaded and expanded the Montgomery factor.
This doesn't save any stack space because we need 16-byte alignment, but
it does avoid saving and restoring the register.
---

diff --git a/math/mpx-mul4-amd64-sse2.S b/math/mpx-mul4-amd64-sse2.S
index 17c4f1ad..da3e6d61 100644
--- a/math/mpx-mul4-amd64-sse2.S
+++ b/math/mpx-mul4-amd64-sse2.S
@@ -1155,7 +1155,7 @@ FUNC(mpxmont_redc4_amd64_sse2)
 	// outer loop dv	r10	rcx
 	// outer loop dv limit	r11	r11
 	// nv base		rdx	r8
-	// nv limit		r9	r12*
+	// nv limit		r9	r10*
 	// n			rcx	r9
 	// c			rcx	r9
 
@@ -1183,14 +1183,13 @@ FUNC(mpxmont_redc4_amd64_sse2)
 #  define DV rcx
 #  define DVLO r11
 #  define NV r8
-#  define NVL r12
+#  define NVL r10
 #  define N r9
 #  define C r9d
 
 	pushreg	rbx
 	pushreg	rdi
-	pushreg	r12
-	stalloc	160
+	stalloc	168
 
 	savexmm	xmm6,    0
 	savexmm	xmm7,   16
@@ -1300,8 +1299,7 @@ FUNC(mpxmont_redc4_amd64_sse2)
 	rstrxmm	xmm14, 128
 	rstrxmm	xmm15, 144
 
-	stfree	160
-	popreg	r12
+	stfree	168
 	popreg	rdi
 	popreg	rbx
 #endif