Xinu7/man/man1/subEIS.1

.TH SUBEIS 1
.SH NAME
subEIS \- substitute code for \s-2LSI 11\s0 extended instructions
.SH SYNOPSIS
.B subASH
.br
.B subASHC
.br
.B subMUL
.br
.B subDIV
.SH DESCRIPTION
These programs read an \s-2LSI 11\s0 assembly language program from
the standard input,
replace opcodes from the  Extended Instruction
Set (EIS) with a call to a library subroutine that simulates them,
and write the new listing on the standard output.
They are used mainly as filters for compiling \s-2LSI 11/02\s0 programs
for machines without the EIS chip.
.LP
Each program checks for a different instruction;
.I subMUL
checks for (and replaces)
.I mul
instructions,
.I subDIV
checks for (and replaces)
.I div
instructions,
.I subASH
checks for (and replaces)
.I ash
instructions,
and
.I subASHC
checks for (and replaces)
.I ashc
instructions.
The resulting assembly language program must be loaded with
the library
.I libeis.a ,
which contains the routines called.
.SH SEE ALSO
cc11(1), EIS(2)
.SH DIAGNOSTICS
The condition codes are correctly set by the above calling sequence.
.SH BUGS
Setting the condition codes accounts for most of the work these routines
perform.
Unfortunately, they are so slow that most programs, including Xinu
are unusable on an 11/2 without the EIS hardware.