fptrap.3

莱昂氏UNIX源代码分析UNIXv6src.tar.gz

.th FPTRAP III 11/18/73
.sh NAME
fptrap \*- floating point interpreter
.sh SYNOPSIS
.ft B
sys	signal; 4; fptrap
.ft R
.sh DESCRIPTION
.it Fptrap
is a simulator of the
11/45 FP11-B floating point unit.
It works by intercepting illegal instruction
traps
and decoding and executing the floating point operation codes.
.sh FILES
In systems with real floating point,
there is a fake routine in /lib/liba.a with this name;
when simulation is desired,
the real version should be put in liba.a
.sh DIAGNOSTICS
A break point trap is given when a real
illegal instruction trap occurs.
.sh "SEE ALSO"
signal (II),
cc (I) (`\-f' option)
.sh BUGS
Rounding mode is not interpreted.
It's slow.