xnu-792.10.96.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 6e84e601ca0122e5b02cb8f7979e66274a7b2c6b..55bfd27bab4b10879c91edadf2f896132edda863 100644 (file)
--- a/osfmk/i386/commpage/commpage_gettimeofday.s
+++ b/osfmk/i386/commpage/commpage_gettimeofday.s
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003 Apple Computer, Inc. All rights reserved.
+ * Copyright (c) 2003-2006 Apple Computer, Inc. All rights reserved.
  *
  * @APPLE_LICENSE_HEADER_START@
  * 
@@ -24,11 +24,106 @@
 #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    %edi
+       push    %ebx
+
+0:
+       cmp     $0,_COMM_PAGE_TIMEENABLE
+       je      4f
+       mov     _COMM_PAGE_TIMEBASE,%esi
+       mov     _COMM_PAGE_TIMEBASE+4,%edi
+       mov     _COMM_PAGE_TIMESTAMP,%ebx
+
+       mov     $ _COMM_PAGE_NANOTIME,%eax
+       call    *%eax           /* get ns in %edx:%eax */
+
+       cmp     _COMM_PAGE_TIMEBASE,%esi
+       jne     0b
+       cmp     _COMM_PAGE_TIMEBASE+4,%edi
+       jne     0b
+       cmp     $0,_COMM_PAGE_TIMEENABLE
+       je      4f
+       
+       mov     $ NSEC_PER_SEC,%ecx
+       sub     %esi,%eax
+       sbb     %edi,%edx
+       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     %edi
+       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_TIMEBASE),%r10
+0:
+       cmpl    $0,_TIMEENABLE(%r10)    // is data valid? (test _COMM_PAGE_TIMEENABLE)
+       jz      4f                      // no
+       movq    _TIMEBASE(%r10),%r11    // get _COMM_PAGE_TIMEBASE
+       movq    $_COMM_PAGE_32_TO_64(_COMM_PAGE_NANOTIME),%rax
+       call    *%rax                   // get %rax <- nanotime(), preserving %r9, %r10 and %r11
+       movl    _TIMESTAMP(%r10),%r8d   // get _COMM_PAGE_TIMESTAMP
+       cmpq    _TIMEBASE(%r10),%r11    // has _COMM_PAGE_TIMEBASE changed?
+       jne     0b                      // loop until we have consistent data
+       cmpl    $0,_TIMEENABLE(%r10)    // is data valid? (test _COMM_PAGE_TIMEENABLE)
+       jz      4f                      // no
+       
+       movl    $ NSEC_PER_SEC,%ecx
+       subq    %r11,%rax               // generate nanoseconds since timestamp
+       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)