Chapter 6 Applied Instructions API 0105 Symbol: S 1 ： Minuend Double word/Long word S 2 ： SubtrAH500end Double word/Long word D ： Difference Double word/Long word Explanation: 1. The floating-point number in S 2 is subtracted from the floating-point number in S 1 , and the difference is store in D . 2. When the operation result is zero, SM600 is ON. 3. The subtraction of 32-bit single-precision floating-point numbers: When the absolute value of the operation result is less than the value which can be represented by the minimum floating-point number, the value in D is 16#FF7FFFFF.
When the absolute value of the operation result is larger than the value which can be represented by the maximum floating-point number, the value in D is 16#7F7FFFFF. b31.........b16 b15...........b0 S S 1 S 2 +1 S S2 S 1 +1 b31.........b16 b15...........b0 D+1 D - 4. The subtraction of 64-bit double-precision floating-point numbers: When the absolute value of the operation result is less than the value which can be represented by the minimum floating-point number, the value in D is 16#FFEFFFFFFFFFFFFF. When the absolute value of the operation result is larger than the value which can be represented by the maximum floating-point number, the value in D is 16#7FEFFFFFFFFFFFFF.
b31.........b16 = b15...........b0 6-47 Instruction code Operand Function D F- P S , S , D 1 2 Subtraction of floating-point numbers Device X Y M S T C HC D L SM SR E PR K 16# “$” DF S 1 S 2 D Pulse instruction 32-bit instruction (7-9 steps) 64-bit instruction (7-9 steps) AH500 AH500 AH500