Interpreting the contents of a floating-point register

There are thirty-two 64-bit floating-point registers. The floating-point register is used to execute the instruction.

There are thirty-two 64-bit floating-point registers, numbered from floating-point register 0-31. All floating-point instructions provide a 5-bit field that specifies which floating-point registers to use in the execution of the instruction. Every instruction that interprets the contents of a floating-point register as a floating-point value uses the double-precision floating-point format for this interpretation.

All floating-point instructions other than loads and stores are performed on operands located in floating-point registers and place the results in a floating-point register. The Floating-Point Status and Control Register and the Condition Register maintain status information about the outcome of some floating-point operations.

Load and store double instructions transfer 64 bits of data without conversion between storage and a floating-point register in the floating-point processor. Load single instructions convert a stored single floating-format value to the same value in double floating format and transfer that value into a floating-point register. Store single instructions do the opposite, converting valid single-precision values in a floating-point register into a single floating-format value, prior to storage.