Java Virtual Machine (Java Series)

dcmpg

dcmpg

Stack

This takes two double-precision floating point numbers off the operand stack and compares them, using IEEE 754 rules.

If the two numbers are the same, the int 0 is pushed onto the stack. If value2 is greater than value1, the int 1 is pushed onto the stack. If value1 is greater than value2, -1 is pushed onto the stack. If either numbers is NaN, the int 1 is pushed onto the stack. +0.0 and -0.0 are treated as equal.

Example

dload_1 ; push the double in local variable 1 dconst_0 ; push the double 0.0 onto the stack dcmpg ; compare the two numbers ; The integer result on the stack is: ; 0 if local variable 1 equals 0 ; -1 if local variable 1 is less than 0 ; 1 if local variable 1 is greater than 0 Bytecode

lcmp, fcmpl, fcmpg, dcmpl

Notes

This instruction is identical to dcmpl except for the treatment of NaN.

Java Virtual Machine, by Jon Meyer and Troy Downing, O'Reilly Associates