svn commit: r285355 - head/sys/i386/isa

[Konstantin Belousov]

Author: kib
Date: Fri Jul 10 09:20:13 2015
New Revision: 285355
URL: https://svnweb.freebsd.org/changeset/base/285355

Log:
  Convert between abridged (from FXSAVE) and unabridged (from FSAVE)
  versions of the x87 tags.  The conversion is naive, used abridged tag
  is converted to valid unabridged, without additional checks for zero
  and special values.
  
  Noted by:	bde
  Sponsored by:	The FreeBSD Foundation
  MFC after:	1 week

Modified:
  head/sys/i386/isa/npx.c

Modified: head/sys/i386/isa/npx.c
==============================================================================
--- head/sys/i386/isa/npx.c	Fri Jul 10 09:15:06 2015	(r285354)
+++ head/sys/i386/isa/npx.c	Fri Jul 10 09:20:13 2015	(r285355)
@@ -1173,16 +1173,20 @@ npx_fill_fpregs_xmm1(struct savexmm *sv_
 	/* FPU control/status */
 	penv_87->en_cw = penv_xmm->en_cw;
 	penv_87->en_sw = penv_xmm->en_sw;
-	penv_87->en_tw = penv_xmm->en_tw;
 	penv_87->en_fip = penv_xmm->en_fip;
 	penv_87->en_fcs = penv_xmm->en_fcs;
 	penv_87->en_opcode = penv_xmm->en_opcode;
 	penv_87->en_foo = penv_xmm->en_foo;
 	penv_87->en_fos = penv_xmm->en_fos;
 
-	/* FPU registers */
-	for (i = 0; i < 8; ++i)
+	/* FPU registers and tags */
+	penv_87->en_tw = 0xffff;
+	for (i = 0; i < 8; ++i) {
 		sv_87->sv_ac[i] = sv_xmm->sv_fp[i].fp_acc;
+		if ((penv_xmm->en_tw & (1 << i)) != 0)
+			/* zero and special are set as valid */
+			penv_87->en_tw &= ~(3 << i);
+	}
 }
 
 void
@@ -1206,16 +1210,19 @@ npx_set_fpregs_xmm(struct save87 *sv_87,
 	/* FPU control/status */
 	penv_xmm->en_cw = penv_87->en_cw;
 	penv_xmm->en_sw = penv_87->en_sw;
-	penv_xmm->en_tw = penv_87->en_tw;
 	penv_xmm->en_fip = penv_87->en_fip;
 	penv_xmm->en_fcs = penv_87->en_fcs;
 	penv_xmm->en_opcode = penv_87->en_opcode;
 	penv_xmm->en_foo = penv_87->en_foo;
 	penv_xmm->en_fos = penv_87->en_fos;
 
-	/* FPU registers */
-	for (i = 0; i < 8; ++i)
+	/* FPU registers and tags */
+	penv_xmm->en_tw = 0;
+	for (i = 0; i < 8; ++i) {
 		sv_xmm->sv_fp[i].fp_acc = sv_87->sv_ac[i];
+		if ((penv_87->en_tw && (3 << i)) != (3 << i))
+		    penv_xmm->en_tw |= 1 << i;
+	}
 }
 #endif /* CPU_ENABLE_SSE */