1/* 2 * Copyright (c) 2003-2005 Apple Computer, Inc. All rights reserved. 3 * 4 * @APPLE_OSREFERENCE_LICENSE_HEADER_START@ 5 * 6 * This file contains Original Code and/or Modifications of Original Code 7 * as defined in and that are subject to the Apple Public Source License 8 * Version 2.0 (the 'License'). You may not use this file except in 9 * compliance with the License. The rights granted to you under the License 10 * may not be used to create, or enable the creation or redistribution of, 11 * unlawful or unlicensed copies of an Apple operating system, or to 12 * circumvent, violate, or enable the circumvention or violation of, any 13 * terms of an Apple operating system software license agreement. 14 * 15 * Please obtain a copy of the License at 16 * http://www.opensource.apple.com/apsl/ and read it before using this file. 17 * 18 * The Original Code and all software distributed under the License are 19 * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER 20 * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES, 21 * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY, 22 * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT. 23 * Please see the License for the specific language governing rights and 24 * limitations under the License. 25 * 26 * @APPLE_OSREFERENCE_LICENSE_HEADER_END@ 27 */ 28 29#include <sys/appleapiopts.h> 30#include <ppc/asm.h> // EXT, LEXT 31#include <machine/cpu_capabilities.h> 32#include <machine/commpage.h> 33 34/* The red zone is used to move data between GPRs and FPRs: */ 35 36#define rzTicks -8 // elapsed ticks since timestamp (double) 37#define rzSeconds -16 // seconds since timestamp (double) 38#define rzUSeconds -24 // useconds since timestamp (double) 39 40 41 .text 42 .align 2 43 44 45// ********************************* 46// * G E T T I M E O F D A Y _ 3 2 * 47// ********************************* 48// 49// This is a subroutine of gettimeofday.c that gets the seconds and microseconds 50// in user mode, usually without having to make a system call. We do not deal with 51// the timezone. The kernel maintains the following values in the comm page: 52// 53// _COMM_PAGE_TIMESTAMP = 64 bit seconds timestamp 54// 55// _COMM_PAGE_TIMEBASE = the timebase at which the timestamp was valid 56// 57// _COMM_PAGE_SEC_PER_TICK = multiply timebase ticks by this to get seconds (double) 58// 59// _COMM_PAGE_2_TO_52 = double precision constant 2**52 60// 61// _COMM_PAGE_10_TO_6 = double precision constant 10**6 62// 63// We have to be careful to read these values atomically. The kernel updates them 64// asynchronously to account for drift or time changes (eg, ntp.) We adopt the 65// convention that (timebase==0) means the timestamp is invalid, in which case we 66// return a bad status so our caller can make the system call. 67// 68// r3 = ptr to user's timeval structure (should not be null) 69 70gettimeofday_32: // int gettimeofday(timeval *tp); 710: 72 lwz r5,_COMM_PAGE_TIMEBASE+0(0) // r5,r6 = TBR at timestamp 73 lwz r6,_COMM_PAGE_TIMEBASE+4(0) 74 lwz r8,_COMM_PAGE_TIMESTAMP+4(0) // r8 = timestamp 32 bit seconds 75 lfd f1,_COMM_PAGE_SEC_PER_TICK(0) 761: 77 mftbu r10 // r10,r11 = current timebase 78 mftb r11 79 mftbu r12 80 cmplw r10,r12 81 bne- 1b 82 or. r0,r5,r6 // timebase 0? (ie, is timestamp invalid?) 83 84 sync // create a barrier (patched to NOP if UP) 85 86 lwz r0,_COMM_PAGE_TIMEBASE+0(0) // then load data a 2nd time 87 lwz r12,_COMM_PAGE_TIMEBASE+4(0) 88 lwz r9,_COMM_PAGE_TIMESTAMP+4(0) 89 cmplw cr6,r5,r0 // did we read a consistent set? 90 cmplw cr7,r6,r12 91 beq- 3f // timestamp is disabled so return bad status 92 cmplw cr5,r9,r8 93 crand cr0_eq,cr6_eq,cr7_eq 94 crand cr0_eq,cr0_eq,cr5_eq 95 bne- 0b // loop until we have a consistent set of data 96 97 subfc r11,r6,r11 // compute ticks since timestamp 98 lwz r9,_COMM_PAGE_2_TO_52(0) // get exponent for (2**52) 99 subfe r10,r5,r10 // complete 64-bit subtract 100 lfd f2,_COMM_PAGE_2_TO_52(0) // f2 <- (2**52) 101 srwi. r0,r10,2 // if more than 2**34 ticks have elapsed... 102 stw r11,rzTicks+4(r1) // store elapsed ticks into red zone 103 or r10,r10,r9 // convert long-long in (r10,r11) into double 104 bne- 3f // ...call kernel to reprime timestamp 105 106 stw r10,rzTicks(r1) // complete double 107 108 mffs f7 109 mtfsfi 7,1 110 lfd f3,rzTicks(r1) // get elapsed ticks since timestamp + 2**52 111 fsub f4,f3,f2 // subtract 2**52 and normalize 112 fmul f5,f4,f1 // f5 <- elapsed seconds since timestamp 113 lfd f3,_COMM_PAGE_10_TO_6(0) // get 10**6 114 fctiwz f6,f5 // convert to integer 115 stfd f6,rzSeconds(r1) // store integer seconds into red zone 116 stw r9,rzSeconds(r1) // prepare to reload as floating pt 117 lfd f6,rzSeconds(r1) // get seconds + 2**52 118 fsub f6,f6,f2 // f6 <- integral seconds 119 fsub f6,f5,f6 // f6 <- fractional part of elapsed seconds 120 fmul f6,f6,f3 // f6 <- fractional elapsed useconds 121 fctiwz f6,f6 // convert useconds to integer 122 stfd f6,rzUSeconds(r1) // store useconds into red zone 123 mtfsf 0xff,f7 124 125 lwz r5,rzSeconds+4(r1) // r5 <- seconds since timestamp 126 lwz r7,rzUSeconds+4(r1) // r7 <- useconds since timestamp 127 add r6,r8,r5 // add elapsed seconds to timestamp seconds 128 129 stw r6,0(r3) // store secs//usecs into user's timeval 130 stw r7,4(r3) 131 li r3,0 // return success 132 blr 1333: // too long since last timestamp or this code is disabled 134 li r3,1 // return bad status so our caller will make syscall 135 blr 136 137 COMMPAGE_DESCRIPTOR(gettimeofday_32,_COMM_PAGE_GETTIMEOFDAY,0,k64Bit,kCommPageSYNC+kCommPage32) 138 139 140// *************************************** 141// * G E T T I M E O F D A Y _ G 5 _ 3 2 * 142// *************************************** 143// 144// This routine is called in 32-bit mode on 64-bit processors. A timeval is a struct of 145// a long seconds and int useconds, so its size depends on mode. 146 147gettimeofday_g5_32: // int gettimeofday(timeval *tp); 1480: 149 ld r6,_COMM_PAGE_TIMEBASE(0) // r6 = TBR at timestamp 150 ld r8,_COMM_PAGE_TIMESTAMP(0) // r8 = timestamp (seconds) 151 lfd f1,_COMM_PAGE_SEC_PER_TICK(0) 152 mftb r10 // r10 = get current timebase 153 lwsync // create a barrier if MP (patched to NOP if UP) 154 ld r11,_COMM_PAGE_TIMEBASE(0) // then get data a 2nd time 155 ld r12,_COMM_PAGE_TIMESTAMP(0) 156 cmpdi cr1,r6,0 // is the timestamp disabled? 157 cmpld cr6,r6,r11 // did we read a consistent set? 158 cmpld cr7,r8,r12 159 beq-- cr1,3f // exit if timestamp disabled 160 crand cr6_eq,cr7_eq,cr6_eq 161 sub r11,r10,r6 // compute elapsed ticks from timestamp 162 bne-- cr6,0b // loop until we have a consistent set of data 163 164 srdi. r0,r11,35 // has it been more than 2**35 ticks since last timestamp? 165 std r11,rzTicks(r1) // put ticks in redzone where we can "lfd" it 166 bne-- 3f // timestamp too old, so reprime 167 168 mffs f7 169 mtfsfi 7,1 170 lfd f3,rzTicks(r1) // get elapsed ticks since timestamp (fixed pt) 171 fcfid f4,f3 // float the tick count 172 fmul f5,f4,f1 // f5 <- elapsed seconds since timestamp 173 lfd f3,_COMM_PAGE_10_TO_6(0) // get 10**6 174 fctidz f6,f5 // convert integer seconds to fixed pt 175 stfd f6,rzSeconds(r1) // save fixed pt integer seconds in red zone 176 fcfid f6,f6 // float the integer seconds 177 fsub f6,f5,f6 // f6 <- fractional part of elapsed seconds 178 fmul f6,f6,f3 // f6 <- fractional elapsed useconds 179 fctidz f6,f6 // convert useconds to fixed pt integer 180 stfd f6,rzUSeconds(r1) // store useconds into red zone 181 mtfsf 0xff,f7 182 183 lwz r5,rzSeconds+4(r1) // r5 <- seconds since timestamp 184 lwz r7,rzUSeconds+4(r1) // r7 <- useconds since timestamp 185 add r6,r8,r5 // add elapsed seconds to timestamp seconds 186 187 stw r6,0(r3) // store secs//usecs into user's timeval 188 stw r7,4(r3) 189 li r3,0 // return success 190 blr 1913: // too long since last timestamp or this code is disabled 192 li r3,1 // return bad status so our caller will make syscall 193 blr 194 195 COMMPAGE_DESCRIPTOR(gettimeofday_g5_32,_COMM_PAGE_GETTIMEOFDAY,k64Bit,0,kCommPageSYNC+kCommPage32) 196 197 198// *************************************** 199// * G E T T I M E O F D A Y _ G 5 _ 6 4 * 200// *************************************** 201// 202// This routine is called in 64-bit mode on 64-bit processors. A timeval is a struct of 203// a long seconds and int useconds, so its size depends on mode. 204 205gettimeofday_g5_64: // int gettimeofday(timeval *tp); 2060: 207 ld r6,_COMM_PAGE_TIMEBASE(0) // r6 = TBR at timestamp 208 ld r8,_COMM_PAGE_TIMESTAMP(0) // r8 = timestamp (seconds) 209 lfd f1,_COMM_PAGE_SEC_PER_TICK(0) 210 mftb r10 // r10 = get current timebase 211 lwsync // create a barrier if MP (patched to NOP if UP) 212 ld r11,_COMM_PAGE_TIMEBASE(0) // then get data a 2nd time 213 ld r12,_COMM_PAGE_TIMESTAMP(0) 214 cmpdi cr1,r6,0 // is the timestamp disabled? 215 cmpld cr6,r6,r11 // did we read a consistent set? 216 cmpld cr7,r8,r12 217 beq-- cr1,3f // exit if timestamp disabled 218 crand cr6_eq,cr7_eq,cr6_eq 219 sub r11,r10,r6 // compute elapsed ticks from timestamp 220 bne-- cr6,0b // loop until we have a consistent set of data 221 222 srdi. r0,r11,35 // has it been more than 2**35 ticks since last timestamp? 223 std r11,rzTicks(r1) // put ticks in redzone where we can "lfd" it 224 bne-- 3f // timestamp too old, so reprime 225 226 mffs f7 227 mtfsfi 7,1 228 lfd f3,rzTicks(r1) // get elapsed ticks since timestamp (fixed pt) 229 fcfid f4,f3 // float the tick count 230 fmul f5,f4,f1 // f5 <- elapsed seconds since timestamp 231 lfd f3,_COMM_PAGE_10_TO_6(0) // get 10**6 232 fctidz f6,f5 // convert integer seconds to fixed pt 233 stfd f6,rzSeconds(r1) // save fixed pt integer seconds in red zone 234 fcfid f6,f6 // float the integer seconds 235 fsub f6,f5,f6 // f6 <- fractional part of elapsed seconds 236 fmul f6,f6,f3 // f6 <- fractional elapsed useconds 237 fctidz f6,f6 // convert useconds to fixed pt integer 238 stfd f6,rzUSeconds(r1) // store useconds into red zone 239 mtfsf 0xff,f7 240 241 lwz r5,rzSeconds+4(r1) // r5 <- seconds since timestamp 242 lwz r7,rzUSeconds+4(r1) // r7 <- useconds since timestamp 243 add r6,r8,r5 // add elapsed seconds to timestamp seconds 244 245 std r6,0(r3) // store secs//usecs into user's timeval 246 stw r7,8(r3) 247 li r3,0 // return success 248 blr 2493: // too long since last timestamp or this code is disabled 250 li r3,1 // return bad status so our caller will make syscall 251 blr 252 253 COMMPAGE_DESCRIPTOR(gettimeofday_g5_64,_COMM_PAGE_GETTIMEOFDAY,k64Bit,0,kCommPageSYNC+kCommPage64) 254 255 256