[coreboot] [PATCH][v2] Unify CAR for K8 and Fam10h CPUs

Carl-Daniel Hailfinger c-d.hailfinger.devel.2006 at gmx.net
Fri Feb 13 14:44:20 CET 2009

On 13.02.2009 14:01, Patrick Georgi wrote:
> Am Freitag 13 Februar 2009 13:42:15 schrieb Carl-Daniel Hailfinger:
>> This is absolutely awesome! Not only did you manage to keep the code
>> readable, you also have kept the changes localized and really minimal.
>> Although I had something similar (untested, unfinished) on disk, your
>> solution is clearly the way to go. No doubt about that.
> Thank you!
>> I'd ack straight away, but there is one thing I couldn't figure out
>> immediately from the code: Can the code handle Fam11h processors? AFAIK
>> they have to be treated like Fam10h.
> Right. A better way would be to compare against the K8 CPUID, and switch the 
> jump direction in jmp_if_k8. That should be enough, until AMD decides to 
> devise a new scheme for future CPU generations.

I created a patch against a tree with your original patch applied. It
should be able to handle all generations since the invention of CPUID
just fine. Fam11h and later are handled as well.

Signed-off-by: Carl-Daniel Hailfinger <c-d.hailfinger.devel.2006 at gmx.net>

--- corebootv2/src/cpu/amd/car/cache_as_ram.inc	(Arbeitskopie)
+++ corebootv2/src/cpu/amd/car/cache_as_ram.inc	(working copy)
@@ -27,10 +27,10 @@
 /* for CAR_FAM10 */
 #define CacheSizeAPStack 0x400 /* 1K */
-#define jmp_if_k8(x)	comisd	%xmm1, %xmm2; jnz x
+#define jmp_if_k8(x)	comisd	%xmm1, %xmm2; jb x
 #define CPUID_MASK		0x0ff00f00
-#define CPUID_MASK_FAM10	0x00100f00
+#define CPUID_VAL_FAM10_ROTATED	0x0f000010
 #include <cpu/x86/mtrr.h>
 #include <cpu/amd/mtrr.h>
@@ -60,9 +60,12 @@
 	cvtsi2sd %ebx, %xmm3
 	movl	$0x01, %eax
+	/* base family is bits 8..11, extended family is bits 20..27 */
 	andl	$CPUID_MASK, %eax
+	/* reorder bits for easier comparison by value */
+	rol	%eax, $16
 	cvtsi2sd %eax, %xmm1
-	movl	$CPUID_MASK_FAM10, %eax
+	movl	$CPUID_VAL_FAM10_ROTATED, %eax
 	cvtsi2sd %eax, %xmm2
 	cvtsd2si %xmm3, %ebx



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