Converts hexadecimal positive binary values to either integer
(fixed-point) or real (floating-point) values.
| Width range: |
1- 16
|
| Default width: |
8
|
| Alignment: |
left
|
| CMS specifics: |
IBM floating-point format
|
-
w
-
specifies the field width of the output
value and determines whether the output is an integer or real binary value.
The HEX format converts real binary (floating-point)
numbers to hexadecimal representation. Each hexadecimal digit that is written
in the EBCDIC code uses one byte per digit. For example, the floating-point
number 1.0 has the hexadecimal value 'F1'x (EBCDIC 1) using the HEX1. format.
The w value of the HEX format determines
the width of the value and whether the number is written as a floating-point
number or an integer. When you specify a width value of 1 through 15, the
real binary numbers are truncated to fixed-point integers before being written
to hexadecimal values. However, when you specify 16 for the width, the floating-point
value is written and the numbers are not truncated. For example, if the value
of Y is 31.5, and you use the following PUT statement to write it to the SAS
log, the following hexadecimal value is written in EBCDIC code:
put y hex16.;
421F800000000000
('F4F2F1C6F8F0F0F0F0F0F0F0F0F0F0F0'x)
The result shows the hexadecimal value for the CMS floating-point
representation of 31.5. The value of a floating-point number is as follows:
the first bit of this number is the sign bit and the next seven bits are the
characteristic, or exponent. Since the sign bit is 0, the number is positive.
To calculate the exponent from the characteristic, you must subtract hexadecimal
40 from the number. Subtracting '40'x from '42'x gives a difference of '02'x.
Thus, the exponent is 216. The last part of the floating-point
number, bits 8 through 63, represents the fraction. Since the exponent is
216 , the radix point is moved two places to the right,
giving a value of '1F.8'x, which is the hexadecimal equivalent of decimal
31.5.
If you set the variable Y equal to -31.5, you get the
following result with a width of 16 specified:
C21F800000000000 ('C3F2F1C6F8F0F0F0'x)
The only difference between this example and the first
example is the changing of the first digit from '4'x to 'C'x. This occurs
because the sign bit has been changed from 0 to 1 if you set the variable
Y equal to -31.5.
However, if you change the format to HEX15. in the first
example, the result writes the following hexadecimal value in EBCDIC code:
'00000000000001F'x ('F0F0F0F0F0F0F1C6'x)
This example illustrates the result when a width value
of less than 16 is specified. Here, the SAS System first converts 31.5 to
an integer by truncating the number to 31. The result is then printed in
the specified number of hexadecimal digits.
With a width of less than 16, a negative floating-point
number is first truncated to an integer and then printed in twos complement
form. Therefore, when the format HEX15. is specified for Y=-31.5, the result
is as follows:
FFFFFFFFFFFFFE1 ('C6C6C6C6C6C6C5F1'x)
Copyright © 1999 by SAS Institute Inc., Cary, NC, USA. All rights reserved.
