blob: 4216d38d278da6b418e074af594cd9e1351d00b2 (
plain) (
blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
|
# Copyright(c) 1986 Association of Universities for Research in Astronomy Inc.
# ARCZ -- Vector reciprocal with checking for zero divisors. If the result
# of a divide would be undefined a user supplied function is called to get the
# output pixel value.
#
# NOTE: in the interests of simplicity a somewhat arbitrary tolerance is used
# to check for an undefined divide, i.e., a divide by zero or a divide by a
# number small enough to cause floating point overflow. A better way to do
# this would be to provide a machine dependent version of this operator in
# host$as which catches the hardware exception rather than using a comparison.
procedure arczs (a, b, c, npix, errfcn)
short a # numerator
short b[ARB], c[ARB] # divisor, and output arrays
int npix # number of pixels
short errfcn() # user function, called on divide by zero
int i
short divisor
extern errfcn()
errchk errfcn
begin
if (a == 0) {
call aclrs (c, npix)
return
}
do i = 1, npix {
divisor = b[i]
if (divisor == 0)
c[i] = errfcn (a)
else
c[i] = a / divisor
}
end
|
