xnu-792.18.15.tar.gz

[apple/xnu.git] / osfmk / i386 / commpage / commpage_mach_absolute_time.s

diff --git a/osfmk/i386/commpage/commpage_mach_absolute_time.s b/osfmk/i386/commpage/commpage_mach_absolute_time.s
index 85969ce93dd1c2cdbb65b6340164079dd09168f5..1cacdb5b2bfacd7912605f1d71a9d47939652fd7 100644 (file)
--- a/osfmk/i386/commpage/commpage_mach_absolute_time.s
+++ b/osfmk/i386/commpage/commpage_mach_absolute_time.s
@@ -1,16 +1,19 @@
 /*
- * Copyright (c) 2003 Apple Computer, Inc. All rights reserved.
+ * Copyright (c) 2003-2006 Apple Computer, Inc. All rights reserved.
  *
- * @APPLE_LICENSE_HEADER_START@
- * 
- * Copyright (c) 1999-2003 Apple Computer, Inc.  All Rights Reserved.
+ * @APPLE_OSREFERENCE_LICENSE_HEADER_START@
  * 
  * This file contains Original Code and/or Modifications of Original Code
  * as defined in and that are subject to the Apple Public Source License
  * Version 2.0 (the 'License'). You may not use this file except in
- * compliance with the License. Please obtain a copy of the License at
- * http://www.opensource.apple.com/apsl/ and read it before using this
- * file.
+ * compliance with the License. The rights granted to you under the License
+ * may not be used to create, or enable the creation or redistribution of,
+ * unlawful or unlicensed copies of an Apple operating system, or to
+ * circumvent, violate, or enable the circumvention or violation of, any
+ * terms of an Apple operating system software license agreement.
+ * 
+ * Please obtain a copy of the License at
+ * http://www.opensource.apple.com/apsl/ and read it before using this file.
  * 
  * The Original Code and all software distributed under the License are
  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
@@ -20,12 +23,15 @@
  * Please see the License for the specific language governing rights and
  * limitations under the License.
  * 
- * @APPLE_LICENSE_HEADER_END@
+ * @APPLE_OSREFERENCE_LICENSE_HEADER_END@
  */
 
 #include <sys/appleapiopts.h>
 #include <machine/cpu_capabilities.h>
 #include <machine/commpage.h>
+#include <i386/asm.h>
+
+#include <assym.s>
 
         .text
         .align  2, 0x90
@@ -35,3 +41,83 @@ Lmach_absolute_time:
        ret
 
        COMMPAGE_DESCRIPTOR(mach_absolute_time,_COMM_PAGE_ABSOLUTE_TIME,0,0)
+
+/* Nanotime is being moved out of the way of bcopy in the commpage.
+ * First we put it in both places, old and new.  Then, when all the build
+ * trains have rebuilt libSystem, we can remove the deprecated instance.
+ */
+ 
+/* return nanotime in %edx:%eax */
+Lold_nanotime:
+Lnanotime:
+       push    %ebp
+       mov     %esp,%ebp
+       push    %esi
+       push    %edi
+       push    %ebx
+
+0:
+       mov     _COMM_PAGE_NT_TSC_BASE,%esi
+       mov     _COMM_PAGE_NT_TSC_BASE+4,%edi
+
+       rdtsc
+       sub     %esi,%eax
+       sbb     %edi,%edx
+
+       mov     _COMM_PAGE_NT_SCALE,%ecx
+
+       mov     %edx,%ebx
+       mull    %ecx
+       mov     %ebx,%eax
+       mov     %edx,%ebx
+       mull    %ecx
+       add     %ebx,%eax
+       adc     $0,%edx
+
+       add     _COMM_PAGE_NT_NS_BASE,%eax
+       adc     _COMM_PAGE_NT_NS_BASE+4,%edx
+
+       cmp     _COMM_PAGE_NT_TSC_BASE,%esi
+       jne     0b
+       cmp     _COMM_PAGE_NT_TSC_BASE+4,%edi
+       jne     0b
+
+       pop     %ebx
+       pop     %edi
+       pop     %esi
+       pop     %ebp
+       ret
+
+       COMMPAGE_DESCRIPTOR(nanotime,_COMM_PAGE_NANOTIME,0,0)
+       COMMPAGE_DESCRIPTOR(old_nanotime,_COMM_PAGE_OLD_NANOTIME,0,0)
+
+
+/* The 64-bit version.  We return the 64-bit nanotime in %rax,
+ * and by convention we must preserve %r9, %r10, and %r11.
+ */
+       .text
+       .align  2
+       .code64
+Lold_nanotime_64:
+Lnanotime_64:                          // NB: must preserve r9, r10, and r11
+       pushq   %rbp                    // set up a frame for backtraces
+       movq    %rsp,%rbp
+       movq    $_COMM_PAGE_32_TO_64(_COMM_PAGE_NT_TSC_BASE),%rsi
+1:
+       movq    _NT_TSC_BASE(%rsi),%r8  // r8  := base_tsc
+       rdtsc                           // edx:eax := tsc
+       shlq    $32,%rdx                // rax := ((edx << 32) | eax), ie 64-bit tsc
+       orq     %rdx,%rax
+       subq    %r8, %rax               // rax := (tsc - base_tsc)
+       movl    _NT_SCALE(%rsi),%ecx
+       mulq    %rcx                    // rdx:rax := (tsc - base_tsc) * scale
+       shrdq   $32,%rdx,%rax           // _COMM_PAGE_NT_SHIFT is always 32
+       addq    _NT_NS_BASE(%rsi),%rax  // (((tsc - base_tsc) * scale) >> 32) + ns_base
+       
+       cmpq    _NT_TSC_BASE(%rsi),%r8  // did the data change during computation?
+       jne     1b
+       popq    %rbp
+       ret
+
+       COMMPAGE_DESCRIPTOR(nanotime_64,_COMM_PAGE_NANOTIME,0,0)
+       COMMPAGE_DESCRIPTOR(old_nanotime_64,_COMM_PAGE_OLD_NANOTIME,0,0)