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The current implementation does not reliably initialize t0 once. Additionally the initialization requires two calls to _gettimeofday(). Let's sacrifice a byte to keep the initialization status and reduce the maximum number of calls to _gettimeofday(). This has caused issues in an application that invokes clock(). The problematic situation is as follows: 1) The program calls clock() which calls _times(). 2) _gettimeofday(&t0, 0) puts 0 in t0.tv_usec (because less than 1 us has elapsed since the beginning of time). 3) _gettimeofday(&t, 0) puts 1 in t.tv_usec (since now more than 1 us has elapsed since the beginning of time). 4) That call to clock() returns 1 (the value from step 3 minus the value in step 2). 5) The program does a second call to clock(). 6) The code above still sees 0 in t0 so it tries to update t0 again and _gettimeofday(&t0, 0) puts 1 in t0.tv_usec. 7) The _gettimeofday(&t, 0) puts 1 in t.tv_usec (since less than 1us has elapsed since step 3). 8) clock() returns 0 (step 7 minus step 6) and indicates that time is moving backwards. Signed-off-by: Christoph Muellner <cmuellner@gcc.gnu.org>
bfin - Analog Devices Blackfin processor. sparc - Fujitsu Sparclite board. Works on the ex930, ex931, ex933 hp74x - Hewlett Packard HP742 board. Also some support for the hp743. m68hc11 - Motorola 68HC11 or 68HC12 support. m68k - Motorola MVME135 and IDP board. For CPU32 systems. mep - Toshiba Media Processor. pa - WinBond and Oki boards with a PA. mips - R3000 support. Array Tech LSI33k based RAID disk controller. lm32 - Lattice Mico32 simulator. epiphany - Adapteva Epiphany multicore processor. or1k - OpenRISC 1000 processor.