/*
* Copyright (c) 2003-2005 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. 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
* EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
* INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
* Please see the License for the specific language governing rights and
* limitations under the License.
*
* @APPLE_OSREFERENCE_LICENSE_HEADER_END@
*/
#include <sys/appleapiopts.h>
#include <ppc/asm.h> // EXT, LEXT
#include <machine/cpu_capabilities.h>
#include <machine/commpage.h>
/* The red zone is used to move data between GPRs and FPRs: */
#define rzTicks -8 // elapsed ticks since timestamp (double)
#define rzSeconds -16 // seconds since timestamp (double)
#define rzUSeconds -24 // useconds since timestamp (double)
.text
.align 2
// *********************************
// * G E T T I M E O F D A Y _ 3 2 *
// *********************************
//
// This is a subroutine of gettimeofday.c that gets the seconds and microseconds
// in user mode, usually without having to make a system call. We do not deal with
// the timezone. The kernel maintains the following values in the comm page:
//
// _COMM_PAGE_TIMESTAMP = 64 bit seconds timestamp
//
// _COMM_PAGE_TIMEBASE = the timebase at which the timestamp was valid
//
// _COMM_PAGE_SEC_PER_TICK = multiply timebase ticks by this to get seconds (double)
//
// _COMM_PAGE_2_TO_52 = double precision constant 2**52
//
// _COMM_PAGE_10_TO_6 = double precision constant 10**6
//
// We have to be careful to read these values atomically. The kernel updates them
// asynchronously to account for drift or time changes (eg, ntp.) We adopt the
// convention that (timebase==0) means the timestamp is invalid, in which case we
// return a bad status so our caller can make the system call.
//
// r3 = ptr to user's timeval structure (should not be null)
gettimeofday_32: // int gettimeofday(timeval *tp) lwz r5,_COMM_PAGE_TIMEBASE+0(0) // r5,r6 = TBR at timestamp
lwz r6,_COMM_PAGE_TIMEBASE+4(0)
lwz r8,_COMM_PAGE_TIMESTAMP+4(0) // r8 = timestamp 32 bit seconds
lfd f1,_COMM_PAGE_SEC_PER_TICK(0)
1:
mftbu r10 // r10,r11 = current timebase
mftb r11
mftbu r12
cmplw r10,r12
bne- 1b
or. r0,r5,r6 // timebase 0? (ie, is timestamp invalid?)
sync // create a barrier (patched to NOP if UP)
lwz r0,_COMM_PAGE_TIMEBASE+0(0) // then load data a 2nd time
lwz r12,_COMM_PAGE_TIMEBASE+4(0)
lwz r9,_COMM_PAGE_TIMESTAMP+4(0)
cmplw cr6,r5,r0 // did we read a consistent set?
cmplw cr7,r6,r12
beq- 3f // timestamp is disabled so return bad status
cmplw cr5,r9,r8
crand cr0_eq,cr6_eq,cr7_eq
crand cr0_eq,cr0_eq,cr5_eq
bne- 0b // loop until we have a consistent set of data
subfc r11,r6,r11 // compute ticks since timestamp
lwz r9,_COMM_PAGE_2_TO_52(0) // get exponent for (2**52)
subfe r10,r5,r10 // complete 64-bit subtract
lfd f2,_COMM_PAGE_2_TO_52(0) // f2 <- (2**52)
srwi. r0,r10,2 // if more than 2**34 ticks have elapsed...
stw r11,rzTicks+4(r1) // store elapsed ticks into red zone
or r10,r10,r9 // convert long-long in (r10,r11) into double
bne- 3f // ...call kernel to reprime timestamp
stw r10,rzTicks(r1) // complete double
mffs f7
mtfsfi 7,1
lfd f3,rzTicks(r1) // get elapsed ticks since timestamp + 2**52
fsub f4,f3,f2 // subtract 2**52 and normalize
fmul f5,f4,f1 // f5 <- elapsed seconds since timestamp
lfd f3,_COMM_PAGE_10_TO_6(0) // get 10**6
fctiwz f6,f5 // convert to integer
stfd f6,rzSeconds(r1) // store integer seconds into red zone
stw r9,rzSeconds(r1) // prepare to reload as floating pt
lfd f6,rzSeconds(r1) // get seconds + 2**52
fsub f6,f6,f2 // f6 <- integral seconds
fsub f6,f5,f6 // f6 <- fractional part of elapsed seconds
fmul f6,f6,f3 // f6 <- fractional elapsed useconds
fctiwz f6,f6 // convert useconds to integer
stfd f6,rzUSeconds(r1) // store useconds into red zone
mtfsf 0xff,f7
lwz r5,rzSeconds+4(r1) // r5 <- seconds since timestamp
lwz r7,rzUSeconds+4(r1) // r7 <- useconds since timestamp
add r6,r8,r5 // add elapsed seconds to timestamp seconds
stw r6,0(r3) // store secs//usecs into user's timeval
stw r7,4(r3)
li r3,0 // return success
blr
3: // too long since last timestamp or this code is disabled
li r3,1 // return bad status so our caller will make syscall
blr
COMMPAGE_DESCRIPTOR(gettimeofday_32,_COMM_PAGE_GETTIMEOFDAY,0,k64Bit,kCommPageSYNC+kCommPage32)
// ***************************************
// * G E T T I M E O F D A Y _ G 5 _ 3 2 *
// ***************************************
//
// This routine is called in 32-bit mode on 64-bit processors. A timeval is a struct of
// a long seconds and int useconds, so its size depends on mode.
gettimeofday_g5_32: // int gettimeofday(timeval *tp) ld r6,_COMM_PAGE_TIMEBASE(0) // r6 = TBR at timestamp
ld r8,_COMM_PAGE_TIMESTAMP(0) // r8 = timestamp (seconds)
lfd f1,_COMM_PAGE_SEC_PER_TICK(0)
mftb r10 // r10 = get current timebase
lwsync // create a barrier if MP (patched to NOP if UP)
ld r11,_COMM_PAGE_TIMEBASE(0) // then get data a 2nd time
ld r12,_COMM_PAGE_TIMESTAMP(0)
cmpdi cr1,r6,0 // is the timestamp disabled?
cmpld cr6,r6,r11 // did we read a consistent set?
cmpld cr7,r8,r12
beq-- cr1,3f // exit if timestamp disabled
crand cr6_eq,cr7_eq,cr6_eq
sub r11,r10,r6 // compute elapsed ticks from timestamp
bne-- cr6,0b // loop until we have a consistent set of data
srdi. r0,r11,35 // has it been more than 2**35 ticks since last timestamp?
std r11,rzTicks(r1) // put ticks in redzone where we can "lfd" it
bne-- 3f // timestamp too old, so reprime
mffs f7
mtfsfi 7,1
lfd f3,rzTicks(r1) // get elapsed ticks since timestamp (fixed pt)
fcfid f4,f3 // float the tick count
fmul f5,f4,f1 // f5 <- elapsed seconds since timestamp
lfd f3,_COMM_PAGE_10_TO_6(0) // get 10**6
fctidz f6,f5 // convert integer seconds to fixed pt
stfd f6,rzSeconds(r1) // save fixed pt integer seconds in red zone
fcfid f6,f6 // float the integer seconds
fsub f6,f5,f6 // f6 <- fractional part of elapsed seconds
fmul f6,f6,f3 // f6 <- fractional elapsed useconds
fctidz f6,f6 // convert useconds to fixed pt integer
stfd f6,rzUSeconds(r1) // store useconds into red zone
mtfsf 0xff,f7
lwz r5,rzSeconds+4(r1) // r5 <- seconds since timestamp
lwz r7,rzUSeconds+4(r1) // r7 <- useconds since timestamp
add r6,r8,r5 // add elapsed seconds to timestamp seconds
stw r6,0(r3) // store secs//usecs into user's timeval
stw r7,4(r3)
li r3,0 // return success
blr
3: // too long since last timestamp or this code is disabled
li r3,1 // return bad status so our caller will make syscall
blr
COMMPAGE_DESCRIPTOR(gettimeofday_g5_32,_COMM_PAGE_GETTIMEOFDAY,k64Bit,0,kCommPageSYNC+kCommPage32)
// ***************************************
// * G E T T I M E O F D A Y _ G 5 _ 6 4 *
// ***************************************
//
// This routine is called in 64-bit mode on 64-bit processors. A timeval is a struct of
// a long seconds and int useconds, so its size depends on mode.
gettimeofday_g5_64: // int gettimeofday(timeval *tp) ld r6,_COMM_PAGE_TIMEBASE(0) // r6 = TBR at timestamp
ld r8,_COMM_PAGE_TIMESTAMP(0) // r8 = timestamp (seconds)
lfd f1,_COMM_PAGE_SEC_PER_TICK(0)
mftb r10 // r10 = get current timebase
lwsync // create a barrier if MP (patched to NOP if UP)
ld r11,_COMM_PAGE_TIMEBASE(0) // then get data a 2nd time
ld r12,_COMM_PAGE_TIMESTAMP(0)
cmpdi cr1,r6,0 // is the timestamp disabled?
cmpld cr6,r6,r11 // did we read a consistent set?
cmpld cr7,r8,r12
beq-- cr1,3f // exit if timestamp disabled
crand cr6_eq,cr7_eq,cr6_eq
sub r11,r10,r6 // compute elapsed ticks from timestamp
bne-- cr6,0b // loop until we have a consistent set of data
srdi. r0,r11,35 // has it been more than 2**35 ticks since last timestamp?
std r11,rzTicks(r1) // put ticks in redzone where we can "lfd" it
bne-- 3f // timestamp too old, so reprime
mffs f7
mtfsfi 7,1
lfd f3,rzTicks(r1) // get elapsed ticks since timestamp (fixed pt)
fcfid f4,f3 // float the tick count
fmul f5,f4,f1 // f5 <- elapsed seconds since timestamp
lfd f3,_COMM_PAGE_10_TO_6(0) // get 10**6
fctidz f6,f5 // convert integer seconds to fixed pt
stfd f6,rzSeconds(r1) // save fixed pt integer seconds in red zone
fcfid f6,f6 // float the integer seconds
fsub f6,f5,f6 // f6 <- fractional part of elapsed seconds
fmul f6,f6,f3 // f6 <- fractional elapsed useconds
fctidz f6,f6 // convert useconds to fixed pt integer
stfd f6,rzUSeconds(r1) // store useconds into red zone
mtfsf 0xff,f7
lwz r5,rzSeconds+4(r1) // r5 <- seconds since timestamp
lwz r7,rzUSeconds+4(r1) // r7 <- useconds since timestamp
add r6,r8,r5 // add elapsed seconds to timestamp seconds
std r6,0(r3) // store secs//usecs into user's timeval
stw r7,8(r3)
li r3,0 // return success
blr
3: // too long since last timestamp or this code is disabled
li r3,1 // return bad status so our caller will make syscall
blr
COMMPAGE_DESCRIPTOR(gettimeofday_g5_64,_COMM_PAGE_GETTIMEOFDAY,k64Bit,0,kCommPageSYNC+kCommPage64)