Subject floating point puzzle
i'm seeing a crash in in _v2d. unfortunately, i don't
see how this is happening.
8.out 8535: suicide: sys: fp: stack underflow fppc=0x6397 status=0x81e1
pc=0x63a5
however, acid says that the Vlong passed in was all zeros. the code generating
the
call to _v2d is
overflow = v > vmax*scale;
where
uvlong v, vmax;
double scale;
v = 0; vmax = 2000; scale =1.;
acid: _v2d:x
_3_ {
_1_ {
lo 0
hi 0
}
_2_ {
lols 0
loms 0
hils 0
hims 0
}
}
acid: stk()
_v2d(x=0x0)+0x87 /sys/src/libc/386/vlrt.c:107
[etc]
_main+0x31 /sys/src/libc/386/main9.s:16
acid: fpr()
F0 0
F1 -Inf
F2 0
F3 0
F4 0
F5 0
F6 0
F7 0
control 0x027f
status 0x0161
tag 0xffff
ip offset 0x00006397
cs selector 0x0023
opcode 0x1920
data operand offset 0x2d48
operand selector 0x001b
acid: regs()
PC 0x000063a5 _v2d+0x87 /sys/src/libc/386/vlrt.c:107
SP 0xdfffedc8 ECODE 0xf01006bd EFLAG 0x00010646
CS 0x00000023 DS 0x0000001b SS 0x0000001b
GS 0xf010001b FS 0x0000001b ES 0x0000001b
TRAP 0x00000010 math coprocessor error
AX 0x00000000 BX 0x00000000 CX 0x00000000 DX 0x00027254
DI 0x00041920 SI 0x0004191c BP 0xdfffed94
- erik
