Statement List (STL) - DCE FEL ČVUT v Praze

Integer Math Instructions
7.5 *I Multiply ACCU 1 and ACCU 2 as Integer (16-Bit)
Format
*I
Description
Status word
Example
*I (multiply 16-bit integer numbers) multiplies the contents of ACCU 2-L by the
contents of ACCU 1-L. The contents of ACCU 1-L and ACCU 2-L are interpreted as
16-bit integer numbers. The result is stored in accumulator 1 as a 32-bit integer
number. If the status word bits are OV1 = 1 and OS = 1, the result is outside the
range of a 16-bit integer number.
The instruction is executed without regard to, and without affecting, the RLO. The
status word bits CC 1, CC 0, OS, and OV are set as a function of the result of the
instruction.
The contents of accumulator 2 remain unchanged for CPUs with two ACCUs.
The contents of accumulator 3 are copied into accumulator 2, and the contents of
accumulator 4 are copied into accumulator 3 for CPUs with four ACCUs.
See also Evaluating the Bits of the Status Word with Integer Math Instructions.
BR CC 1 CC 0 OV OS OR STA RLO /FC
writes: - x x x x - - - -
Status bit generation CC 1 CC 0 OV OS
Product = 0 0 0 0 -
-32768 = Product > 0 1 0 0 -
1073741824 >= Product > 32767 1 0 1 1
-1073709056