| 摘要 |
PROBLEM TO BE SOLVED: To provide a CPU which has a calculation precision calculating function with which a user can easily recognize a part of a program where the precision may possibly be deteriorated during the execution of calculation and also in the secondary processing that is carried out after the calculation. SOLUTION: An existing double precision floating point data format is extended, and the effective digit number (VD) and the effective precision (E) of the variable value of an arithmetic result can be stored in the extended format. That is, an ALU 11 calculates the numbers (VN) and precision (E) of arithmetic variables stored in the operand register parts 12 and 13 in addition to the numerical value of those variables. Then the ALU 11 holds the calculated numbers (VN) of arithmetic variables at a register part (effective digit number part) 14c and holds the precision (E) of the variables at a register part (effective precision part) 14d respectively. |
