EPICS Base

epicsCalc bit-wise operators on aarch64

Bug #1838792 reported by Andrew Johnson
6
This bug affects 1 person
Affects Status Importance Assigned to Milestone
EPICS Base
Status tracked in 7.0
3.15
Fix Released
Undecided
Unassigned
EPICS Base 3.15.8
7.0
Fix Released
Undecided
Unassigned
EPICS Base 7.0.4

Bug Description

Kiman Ha has reported failures of epicsCalcTest running on a 64-bit ARM system with a quad Cortex-A53 core:

OS : Debian GNU/Linux 10.0
Core Architecture : aarch64
Kernel : 4.19.0
gcc version 8.3.0 (Debian 8.3.0-6)

The failures are identical on Base 3.16.2, 7.0.2.2 and 7.0.3 (no other tests fail):

> not ok 225 - ~~5
> # Expected result is 5, actually got -1
> Integer 5 (0x5)
> BIT_NOT
> BIT_NOT
> not ok 511 - 2 | 1 - 3
> # Expected result is -2, actually got 2
> Integer 2 (0x2)
> Integer 1 (0x1)
> Integer 3 (0x3)
> SUB
> BIT_OR
> not ok 522 - 3 AND -2
> # Expected result is 2, actually got 0
> Integer 3 (0x3)
> Integer 2 (0x2)
> UNARY_NEG
> BIT_AND
> not ok 578 - 0xaaaaaaaa AND 0xffff0000
> # Expected result is 0xaaaa0000 (2863267840), actually got 0x0 (0)
> Integer -1431655766 (0xaaaaaaaa)
> Integer -65536 (0xffff0000)
> BIT_AND
> not ok 579 - 0xaaaaaaaa OR 0xffff0000
> # Expected result is 0xffffaaaa (4294945450), actually got 0x0 (0)
> Integer -1431655766 (0xaaaaaaaa)
> Integer -65536 (0xffff0000)
> BIT_OR
> not ok 580 - 0xaaaaaaaa XOR 0xffff0000
> # Expected result is 0x5555aaaa (1431677610), actually got 0x0 (0)
> Integer -1431655766 (0xaaaaaaaa)
> Integer -65536 (0xffff0000)
> BIT_EXCL_OR
> not ok 581 - ~0xaaaaaaaa
> # Expected result is 0x55555555 (1431655765), actually got 0x0 (0)
> Integer -1431655766 (0xaaaaaaaa)
> BIT_NOT
> not ok 582 - ~~0xaaaaaaaa
> # Expected result is 0xaaaaaaaa (2863311530), actually got 0x0 (0)
> Integer -1431655766 (0xaaaaaaaa)
> BIT_NOT
> BIT_NOT
> not ok 583 - 0xaaaaaaaa >> 8
> # Expected result is 0xffaaaaaa (4289374890), actually got 0x0 (0)
> Integer -1431655766 (0xaaaaaaaa)
> Integer 8 (0x8)
> RIGHT_SHIFT
> not ok 584 - 0xaaaaaaaa << 8
> # Expected result is 0xaaaaaa00 (2863311360), actually got 0x0 (0)
> Integer -1431655766 (0xaaaaaaaa)
> Integer 8 (0x8)
> LEFT_SHIFT
> not ok 585 - a:=0xaaaaaaaa; b:=0xffff0000; a AND b
> # Expected result is 0xaaaa0000 (2863267840), actually got 0x0 (0)
> Integer -1431655766 (0xaaaaaaaa)
> STORE_A
> Integer -65536 (0xffff0000)
> STORE_B
> FETCH_A
> FETCH_B
> BIT_AND
> not ok 586 - a:=0xaaaaaaaa; b:=0xffff0000; a OR b
> # Expected result is 0xffffaaaa (4294945450), actually got 0x0 (0)
> Integer -1431655766 (0xaaaaaaaa)
> STORE_A
> Integer -65536 (0xffff0000)
> STORE_B
> FETCH_A
> FETCH_B
> BIT_OR
> not ok 587 - a:=0xaaaaaaaa; b:=0xffff0000; a XOR b
> # Expected result is 0x5555aaaa (1431677610), actually got 0x0 (0)
> Integer -1431655766 (0xaaaaaaaa)
> STORE_A
> Integer -65536 (0xffff0000)
> STORE_B
> FETCH_A
> FETCH_B
> BIT_EXCL_OR
> not ok 588 - a:=0xaaaaaaaa; ~a
> # Expected result is 0x55555555 (1431655765), actually got 0x0 (0)
> Integer -1431655766 (0xaaaaaaaa)
> STORE_A
> FETCH_A
> BIT_NOT
> not ok 589 - a:=0xaaaaaaaa; ~~a
> # Expected result is 0xaaaaaaaa (2863311530), actually got 0x0 (0)
> Integer -1431655766 (0xaaaaaaaa)
> STORE_A
> FETCH_A
> BIT_NOT
> BIT_NOT
> not ok 590 - a:=0xaaaaaaaa; a >> 8
> # Expected result is 0xffaaaaaa (4289374890), actually got 0x0 (0)
> Integer -1431655766 (0xaaaaaaaa)
> STORE_A
> FETCH_A
> Integer 8 (0x8)
> RIGHT_SHIFT
> not ok 591 - a:=0xaaaaaaaa; a << 8
> # Expected result is 0xaaaaaa00 (2863311360), actually got 0x0 (0)
> Integer -1431655766 (0xaaaaaaaa)
> STORE_A
> FETCH_A
> Integer 8 (0x8)
> LEFT_SHIFT
> not ok 592 - -1431655766.1 OR 0
> # Expected result is 0xaaaaaaaa (2863311530), actually got 0x0 (0)
> Double 1.43166e+09
> UNARY_NEG
> Integer 0 (0x0)
> BIT_OR
> not ok 593 - 2863311530.1 OR 0
> # Expected result is 0xaaaaaaaa (2863311530), actually got 0x0 (0)
> Double 2.86331e+09
> Integer 0 (0x0)
> BIT_OR
> not ok 594 - 0 OR -1431655766.1
> # Expected result is 0xaaaaaaaa (2863311530), actually got 0x0 (0)
> Integer 0 (0x0)
> Double 1.43166e+09
> UNARY_NEG
> BIT_OR
> not ok 595 - 0 OR 2863311530.1
> # Expected result is 0xaaaaaaaa (2863311530), actually got 0x0 (0)
> Integer 0 (0x0)
> Double 2.86331e+09
> BIT_OR
> not ok 596 - -1431655766.1 XOR 0
> # Expected result is 0xaaaaaaaa (2863311530), actually got 0x0 (0)
> Double 1.43166e+09
> UNARY_NEG
> Integer 0 (0x0)
> BIT_EXCL_OR
> not ok 597 - 2863311530.1 XOR 0
> # Expected result is 0xaaaaaaaa (2863311530), actually got 0x0 (0)
> Double 2.86331e+09
> Integer 0 (0x0)
> BIT_EXCL_OR
> not ok 598 - 0 XOR -1431655766.1
> # Expected result is 0xaaaaaaaa (2863311530), actually got 0x0 (0)
> Integer 0 (0x0)
> Double 1.43166e+09
> UNARY_NEG
> BIT_EXCL_OR
> not ok 599 - 0 XOR 2863311530.1
> # Expected result is 0xaaaaaaaa (2863311530), actually got 0x0 (0)
> Integer 0 (0x0)
> Double 2.86331e+09
> BIT_EXCL_OR
> not ok 600 - -1431655766.1 AND 0xffffffff
> # Expected result is 0xaaaaaaaa (2863311530), actually got 0x0 (0)
> Double 1.43166e+09
> UNARY_NEG
> Integer -1 (0xffffffff)
> BIT_AND
> not ok 601 - 2863311530.1 AND 0xffffffff
> # Expected result is 0xaaaaaaaa (2863311530), actually got 0x0 (0)
> Double 2.86331e+09
> Integer -1 (0xffffffff)
> BIT_AND
> not ok 602 - 0xffffffff AND -1431655766.1
> # Expected result is 0xaaaaaaaa (2863311530), actually got 0x0 (0)
> Integer -1 (0xffffffff)
> Double 1.43166e+09
> UNARY_NEG
> BIT_AND
> not ok 603 - 0xffffffff AND 2863311530.1
> # Expected result is 0xaaaaaaaa (2863311530), actually got 0x0 (0)
> Integer -1 (0xffffffff)
> Double 2.86331e+09
> BIT_AND
> not ok 604 - ~ -1431655766.1
> # Expected result is 0x55555555 (1431655765), actually got 0x0 (0)
> Double 1.43166e+09
> UNARY_NEG
> BIT_NOT
> not ok 606 - -1431655766.1 >> 0
> # Expected result is 0xaaaaaaaa (2863311530), actually got 0x0 (0)
> Double 1.43166e+09
> UNARY_NEG
> Integer 0 (0x0)
> RIGHT_SHIFT
> not ok 607 - 2863311530.1 >> 0
> # Expected result is 0xaaaaaaaa (2863311530), actually got 0x0 (0)
> Double 2.86331e+09
> Integer 0 (0x0)
> RIGHT_SHIFT
> not ok 608 - -1431655766.1 >> 0.1
> # Expected result is 0xaaaaaaaa (2863311530), actually got 0x0 (0)
> Double 1.43166e+09
> UNARY_NEG
> Double 0.1
> RIGHT_SHIFT
> not ok 609 - 2863311530.1 >> 0.1
> # Expected result is 0xaaaaaaaa (2863311530), actually got 0x0 (0)
> Double 2.86331e+09
> Double 0.1
> RIGHT_SHIFT
> not ok 610 - -1431655766.1 << 0
> # Expected result is 0xaaaaaaaa (2863311530), actually got 0x0 (0)
> Double 1.43166e+09
> UNARY_NEG
> Integer 0 (0x0)
> LEFT_SHIFT
> not ok 611 - 2863311530.1 << 0
> # Expected result is 0xaaaaaaaa (2863311530), actually got 0x0 (0)
> Double 2.86331e+09
> Integer 0 (0x0)
> LEFT_SHIFT
> not ok 612 - -1431655766.1 << 0.1
> # Expected result is 0xaaaaaaaa (2863311530), actually got 0x0 (0)
> Double 1.43166e+09
> UNARY_NEG
> Double 0.1
> LEFT_SHIFT
> not ok 613 - 2863311530.1 << 0.1
> # Expected result is 0xaaaaaaaa (2863311530), actually got 0x0 (0)
> Double 2.86331e+09
> Double 0.1
> LEFT_SHIFT

Tags: libcom

Related branches

~freddie-akeroyd/epics-base:bit_operations
Andrew Johnson: Approve
mdavidsaver: Needs Fixing
Diff: 369 lines (+88/-48)
7 files modified
src/libCom/calc/calcPerform.c (+38/-23)
src/libCom/calc/postfix.c (+6/-4)
src/libCom/calc/postfixPvt.h (+3/-2)
src/libCom/test/epicsCalcTest.cpp (+22/-6)
src/libCom/test/epicsMathTest.c (+9/-9)
src/std/rec/calcRecord.dbd.pod (+5/-2)
src/std/rec/calcoutRecord.dbd.pod (+5/-2)
Revision history for this message
Martin Konrad (info-martin-konrad) wrote :

On Debian 10 amd64 all tests pass (same compiler version) but a quick test on my Raspberry Pi 3+ running a 32 bit Raspbian confirms this problem. In case of the first failing test, the direct evaluation of the expression "~~5" by the compiler is correct - it is in fact calcPerform() that ends up with a wrong result when performing bitwise operations. The problem also occurs with -O0.

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