From fa080de7afc95aa1c19a6e6fc0e0708ced2eadc4 Mon Sep 17 00:00:00 2001 From: Joseph Hunkeler Date: Wed, 8 Jul 2015 20:46:52 -0400 Subject: Initial commit --- sys/vops/lz/arczs.x | 39 +++++++++++++++++++++++++++++++++++++++ 1 file changed, 39 insertions(+) create mode 100644 sys/vops/lz/arczs.x (limited to 'sys/vops/lz/arczs.x') diff --git a/sys/vops/lz/arczs.x b/sys/vops/lz/arczs.x new file mode 100644 index 00000000..4216d38d --- /dev/null +++ b/sys/vops/lz/arczs.x @@ -0,0 +1,39 @@ +# 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 -- cgit