dcffixqq

Double-Precision Floating-Point Fix to Quadword

dcffixqq RT,RA

Converts a double-precision floating-point value to a quadword integer.

Details

Converts a double-precision decimal floating-point value to a 128-bit signed quadword integer, storing the result in a GPR pair or related register file location. This Floating-Point category instruction does not update condition registers but may set exception flags in FPSCR. The conversion uses the current rounding mode from FPSCR.

Pseudocode Operation

RT ← CONVERT_DFP_TO_INT128(FRA, FPSCR[RN])

Programming Note

The dcffixqq instruction is commonly used for converting double-precision floating-point numbers to integers, rounding towards zero. Ensure that the input value in RA is within the range representable by a quadword integer to avoid overflow or underflow exceptions. This instruction operates at user privilege level and does not require any specific ordering or alignment of registers.

Example

dcffixqq r3, r4

Encoding

Binary Layout
18
0
LI
6
AA
30
LK
31
 
Format X-form
Opcode 0xFC0007C4
Extension Floating-Point
Registers Altered FPSCR

Operands

  • RT
    Target General Purpose Register
  • RA
    Source General Purpose Register