merge

[plan9front.git] / sys / man / 1 / pc

diff --git a/sys/man/1/pc b/sys/man/1/pc
index a3926f19c4ecb52fb0acd4145ea3c668a7805919..287938541de01120b32fba9d3a41380df9047539 100644 (file)
--- a/sys/man/1/pc
+++ b/sys/man/1/pc
@@ -8,7 +8,7 @@ pc \- programmer's calculator
 ]
 .SH DESCRIPTION
 .I Pc
-is an arbitrary precision calculator with a special emphasis on supporting two's complement bit operations and working with different number bases.
+is an arbitrary precision integer calculator with a special emphasis on supporting two's complement bit operations and working with different number bases.
 .PP
 .I Pc
 reads input statements which are either expressions or control statements.
@@ -33,6 +33,9 @@ Expressions can use the C-like operators
 .TP
 .B < >= < <= == !=
 .PP
+The \fB$\fR operator performs sign extension. \fIn\fB$\fIx\fR truncates \fIx\fR to \fIn\fR bits and sign extends.
+If \fIn\fR is omitted, it is inferred from the highest set bit (the result is always ≤ 0 in this case).
+.PP
 Variables can be defined using
 .BR = .
 The builtin variable