xnu-1228.12.14.tar.gz

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

diff --git a/osfmk/i386/commpage/commpage_gettimeofday.s b/osfmk/i386/commpage/commpage_gettimeofday.s
index 61441d433a8ad3dd1298116a9504fa0a2483ca46..a50dd5410402bd7eb871d5b95c1d4c13c11bc323 100644 (file)
--- a/osfmk/i386/commpage/commpage_gettimeofday.s
+++ b/osfmk/i386/commpage/commpage_gettimeofday.s
@@ -1,14 +1,19 @@
 /*
- * Copyright (c) 2003 Apple Computer, Inc. All rights reserved.
+ * Copyright (c) 2003-2007 Apple Inc. All rights reserved.
  *
- * @APPLE_LICENSE_HEADER_START@
+ * @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
@@ -18,18 +23,108 @@
  * 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>
 
+#define NSEC_PER_SEC   1000*1000*1000
+#define NSEC_PER_USEC  1000
+
         .text
         .align  2, 0x90
 
 Lgettimeofday:
-       int     $0x3
+       push    %ebp
+       mov     %esp,%ebp
+       push    %esi
+       push    %ebx
+
+0:
+       movl    _COMM_PAGE_GTOD_GENERATION,%esi /* get generation (0 if disabled) */
+       testl   %esi,%esi                       /* disabled? */
+       jz      4f
+
+       mov     $ _COMM_PAGE_NANOTIME,%eax
+       call    *%eax                           /* get ns in %edx:%eax */
+
+       
+       sub     _COMM_PAGE_GTOD_NS_BASE,%eax
+       sbb     _COMM_PAGE_GTOD_NS_BASE+4,%edx
+       mov     _COMM_PAGE_GTOD_SEC_BASE,%ebx   /* load all the data before checking generation */
+       mov     $ NSEC_PER_SEC,%ecx
+       
+       cmpl    _COMM_PAGE_GTOD_GENERATION,%esi /* has time data changed out from under us? */
+       jne     0b
+       
+       div     %ecx
+       add     %eax,%ebx
+
+       mov     $ NSEC_PER_USEC,%ecx
+       mov     %edx,%eax
+       xor     %edx,%edx
+       div     %ecx
+
+       mov     8(%ebp),%ecx
+       mov     %ebx,(%ecx)
+       mov     %eax,4(%ecx)
+       xor     %eax,%eax
+
+3:
+       pop     %ebx
+       pop     %esi
+       pop     %ebp
        ret
+4:                             /* fail */
+       movl    $1,%eax
+       jmp     3b
 
        COMMPAGE_DESCRIPTOR(gettimeofday,_COMM_PAGE_GETTIMEOFDAY,0,0)
+
+
+       .code64
+        .text
+        .align  2, 0x90
+
+Lgettimeofday_64:                      // %rdi = ptr to timeval
+       pushq   %rbp                    // set up a frame for backtraces
+       movq    %rsp,%rbp
+       movq    %rdi,%r9                // save ptr to timeval
+       movq    $_COMM_PAGE_32_TO_64(_COMM_PAGE_TIME_DATA_START),%r10
+0:
+       movl    _GTOD_GENERATION(%r10),%r11d    // get generation (0 if disabled)
+       testl   %r11d,%r11d             // disabled?
+       jz      4f
+       
+       movq    $_COMM_PAGE_32_TO_64(_COMM_PAGE_NANOTIME),%rax
+       call    *%rax                   // get %rax <- nanotime(), preserving %r9, %r10 and %r11
+       
+       movl    _GTOD_SEC_BASE(%r10),%r8d       // get _COMM_PAGE_TIMESTAMP
+       subq    _GTOD_NS_BASE(%r10),%rax        // generate nanoseconds since timestamp
+       cmpl    _GTOD_GENERATION(%r10),%r11d    // has data changed out from under us?
+       jne     0b
+       
+       movl    $ NSEC_PER_SEC,%ecx
+       movq    %rax,%rdx
+       shrq    $32,%rdx                // get high half of delta in %edx
+       divl    %ecx                    // %eax <- seconds since timestamp, %edx <- nanoseconds
+       addl    %eax,%r8d               // add seconds elapsed to timestamp seconds
+
+       movl    $ NSEC_PER_USEC,%ecx
+       movl    %edx,%eax
+       xorl    %edx,%edx
+       divl    %ecx                    // divide residual ns by 1000 to get residual us in %eax
+       
+       movq    %r8,(%r9)               // store 64-bit seconds into timeval
+       movl    %eax,8(%r9)             // store 32-bit useconds into timeval
+       xorl    %eax,%eax               // return 0 for success
+3:
+       popq    %rbp
+       ret
+4:                                     // fail
+       movl    $1,%eax
+       jmp     3b
+
+       COMMPAGE_DESCRIPTOR(gettimeofday_64,_COMM_PAGE_GETTIMEOFDAY,0,0)