Chapter 6 Applied Instructions API 1514 Symbol: S 1 ： Device in which the base is stored Double word S 2 ： Source device Double word D ： Device in which the operation result is stored Double word Explanation: 1. The logarithm of the value in S 2 with respect to the value in S 1 is calculated, and the operation result is stored in D . 2. The values in S 1 and S 2 only can be positive values. The register specified by D should be a 32-bit register, and the values in S 1 and S 2 should be floating-point numbers. 4. Example: Suppose the values in S 1 and S 2 are 5 and 125 respectively. Find log 5 125. 3. S 1 D = S 2 . → D =Log S1 S 2 . 5. S 1 D = S 2 . → 5 D =125. → D =log 5 125=3. 6.
If the operation result stored in D is 0, SM600 is ON. Example: 1. When X0.0 is ON, the values in (D1, D0) and (D3, D2) are converted into the floating-point numbers, and the conversion results are stored in (D11, D10) and (D13, D12) respectively. 2. When X0.1 is ON, the logarithm of the floating-point number in (D13, D12) with respect to the floating-point number in (D11, D10) is calculated, and the operation result is stored in (D21, D20).
6-343 Instruction code Operand Function FLOG P S , S , D 1 2 Logarithm of the floating-point number Device X Y M S T C HC D L SM SR E PR K 16# “$” DF S 1 S 2 D Pulse instruction 16-bit instruction (7-9 steps) 32-bit instruction AH500 AH500 -