mftb

Move From Timebase

mftb RT,268
mftb RT

Moves the contents of the Time Base Register (TBR) into a general-purpose register.

Details

This instruction behaves as if it were an mfspr instruction. The TBR operand is omitted and assumed to be 268 (the value that corresponds to TB).

Pseudocode Operation

if 'mftb' then
    RT <- TBR[268]

Programming Note

This instruction behaves as if it were an mfspr instruction; see the mfspr instruction description in Section 3.3.19 of Book I. New programs should use mfspr instead of mftb to access the Time Base.

Extended Mnemonics

Extended Mnemonic Equivalent Instruction

Example

mftb r3, 268

Encoding

Binary Layout
31
0
RT
6
268
11
371
31
/
 
Format XFX-form
Opcode 0x7C0002E6
Extension Base
Registers Altered TBR

Operands

  • RT
    Target