sse kernel support (sources)

1 files changed, 14 insertions, 0 deletions

diff --git a/sys/src/9/pc/devarch.c b/sys/src/9/pc/devarch.c
index e877eab5f..be29eab3c 100644
--- a/sys/src/9/pc/devarch.c
+++ b/sys/src/9/pc/devarch.c
@@ -38,6 +38,11 @@ enum {
 
 	Qmax = 16,
 };
+
+enum {
+	CR4Osfxsr = 1 << 9,
+};
+
 enum {				/* cpuid standard function codes */
 	Highstdfunc = 0,	/* also returns vendor string */
 	Procsig,
@@ -850,6 +855,15 @@ cpuidentify(void)
 			rdmsr(0x01, &mct);
 	}
 
+	if(m->cpuiddx & Fxsr){			/* have sse fp? */
+		fpsave = fpssesave;
+		fprestore = fpsserestore;
+		putcr4(getcr4() | CR4Osfxsr);
+	} else {
+		fpsave = fpx87save;
+		fprestore = fpx87restore;
+	}
+
 	cputype = t;
 	return t->family;
 }