Stores a doubleword of data in a specified location in memory and in some cases places the address in a general-purpose register.
| Bits | Value |
|---|---|
| 0-5 | 55 |
| 6-10 | FRS |
| 11-15 | RA |
| 16-31 | D |
| stfdu | FRS, D( RA) |
The stfdu instruction stores the contents of floating-point register (FPR) FRS into the doubleword storage addressed by the effective address (EA).
If general-purpose register (GPR) RA is not 0, the EA is the sum of the contents of GPR RA and D. The sum is a 16-bit signed two's complement integer sign-extended to 32 bits. If GPR RA is 0, then the EA is D.
If GPR RA does not equal 0 and the storage access does not cause Alignment Interrupt or a Data Storage Interrupt, then the EA is stored in GPR RA.
The stfdu instruction has one syntax form and does not affect the Floating-Point Status and Control Register or Condition Register Field 0.
The following code stores the doubleword contents of FPR 6 into a location in memory and stores the address in GPR 4:
.csect data[rw] buffer: .long 0,0 # Assume FPR 6 contains 0x4865 6C6C 6F20 776F. # GPR 4 contains the address of csect data[rw]. .csect text[pr] stfdu 6,buffer(4) # buffer now contains 0x4865 6C6C 6F20 776F. # GPR 4 now contains the address of buffer.
Floating-Point Load and Store Instructions .