Statement List (STL) - DCE FEL ČVUT v Praze

Conversion Instructions
3.18 RND- Round to Lower Double Integer
Format
Description
Status word
Example
RND-
RND- (conversion of a 32-bit IEEE floating-point number to 32-bit integer) interprets
the contents of ACCU 1 as 32-bit IEEE floating-point number. The instruction
converts the 32-bit IEEE floating-point number to a 32-bit integer (double integer)
and rounds the result to the largest whole number less than or equal to the
floating-point number that is converted (IEEE rounding mode "round to -infinity"). If
the number is out of the permissible range, then the status bits OV and OS are set to
1. The result is stored in accumulator 1.
Conversion is not performed and an overflow indicated in the event of a fault
(utilization of a NaN or a floating-point number that cannot be represented as a 32-bit
integer number.)
BR CC 1 CC 0 OV OS OR STA RLO /FC
writes: - - - x x - - - -
STL Explanation
L MD10 //Load the floating-point number into ACCU 1-L.
RND- //Convert the floating-point number (32-bit, IEEE-FP) to an integer (32-bit)
and round result. Store result in ACCU 1.
T MD20 //Transfer result (double integer number) to MD20.
Value before conversion Value after conversion
MD10 = "100.5" => RND- => MD20 = "+100"
MD10 = "-100.5" => RND- => MD20 = "-100"
Statement List (STL) for S7-300 and S7-400 Programming
3-18 A5E00706960-01