| SAS Language Reference: Dictionary |
Integer values are typically stored in one of three
sizes: one-byte, two-byte, or four-byte. The ordering of the bytes for the
integer varies depending on the platform (operating environment) on which
the integers were produced.
The ordering of bytes differs between the "big
endian" and "little endian" platforms. These colloquial
terms are used to describe byte ordering for IBM mainframes (big endian) and
for Intel-based platforms (little endian). In the SAS System, the following
platforms are considered big endian: IBM mainframe, HP-UX, AIX, Solaris, and
Macintosh. The following platforms are considered little endian: VAX/VMS,
AXP/VMS, Digital UNIX, Intel ABI, OS/2, and Windows.
On big endian platforms, the value 1 is stored in binary
and is represented here in hexadecimal notation. One byte is stored as 01,
two bytes as 00 01, and four bytes as 00 00 00 01. On little endian platforms,
the value 1 is stored in one byte as 01 (the same as big endian), in two bytes
as 01 00, and in four bytes as 01 00 00 00.
If an integer is negative,
the "two's complement"
representation is used. The high-order bit of the most significant byte of
the integer will be set on. For example, -2 would be represented in
one, two, and four bytes on big endian platforms as FE, FF FE, and FF FF FF
FE respectively. On little endian platforms, the representation would be FE,
FE FF, and FE FF FF FF.
SAS can read signed and unsigned integers
regardless of whether they were generated on a big endian or a little endian
system. Likewise, SAS can write signed and unsigned integers in both big endian
and little endian format. The length of these integers can be up to eight
bytes.
The following table shows which format to use for various
combinations of platforms. In the Sign? column, "no" indicates
that the number is unsigned and cannot be negative. "Yes" indicates
that the number can be either negative or positive.
The following table compares integer binary notation
according to programming language.
Integer Binary Notation and Programming Languages
|
Language |
2 Bytes |
4 Bytes |
|
SAS |
IB2. , IBR2., PIB2., PIBR2., S370FIB2., S370FIBU2.,
S370FPIB2. |
IB4., IBR4., PIB4., PIBR4., S370FIB4., S370FIBU4., S370FPIB4. |
|
PL/I |
FIXED BIN(15) |
FIXED BIN(31) |
|
FORTRAN |
INTEGER*2 |
INTEGER*4 |
|
COBOL |
COMP PIC 9(4) |
COMP PIC 9(8) |
|
IBM assembler |
H |
F |
|
C |
short |
long |
Copyright © 1999 by SAS Institute Inc., Cary, NC, USA. All rights reserved.
