Convert the contents of a floating-point register to a 64-bit signed fixed-point integer using the round-toward-zero rounding mode. Place the results into another floating-point register.
| Bits | Value |
|---|---|
| 0-5 | 63 |
| 6-10 | D |
| 11-15 | 00000 |
| 16-20 | B |
| 21-30 | 815 |
| 31 | Rc |
| PowerPC | |
|---|---|
| fctidz | FRT, FRB (Rc=0) |
| fctidz. | FRT, FRB (Rc=1) |
The floating-point operand in floating-point register (FRP) FRB is converted to a 64-bit signed fixed-point integer, using the rounding mode round toward zero, and placed into FPR FRT.
If the operand in FPR FRB is greater than 2**63 - 1, then FPR FRT is set to 0x7FFF_FFFF_FFFF_FFFF. If the operand in frB is less than 2**63 , then FPR FRT is set to 0x8000_0000_0000_0000.
Except for enabled invalid operation exceptions, FPSCR[FPRF] is undefined. FPSCR[FR] is set if the result is incremented when rounded. FPSCR[FI] is set if the result is inexact.
The fctidz instruction has two syntax forms. Each syntax form has a different effect on Condition Register Field 1.
| Syntax Form | Floating-Point Status and Control Register | Record Bit (Rc) | Condition Register Field 1 |
| fctidz | FPRF(undefined),FR,FI,FX,XX,VXSNAN,VXCVI | 0 | None |
| fctidz. | FPRF(undefined),FR,FI,FX,XX,VXSNAN,VXCVI | 1 | FX,FEX,VX,OX |
| FRT | Specifies the target floating-point register for the operation. |
| FRB | Specifies the source floating-point register for the operation. |
This instruction is defined only for 64-bit implementations. Using it on a 32-bit implementation will cause the system illegal instruction error handler to be invoked.