Normal, Record, and Overflow Forms

Most integer instructions have four forms:

• normal form - add r3,r4,r5
• record form - add. r3,r4,r5

  This form ends in a period. This form sets register cr0 to whether the result is less, than, equal to, or greater than zero.

• overflow - addo r3,r4,r5

  This form ends in the letter ( o ). This form sets the SO and OV bits in the XER if the result overflows.

• overflow and record - addo. r3,r4,r5

  This form ends in ( o. ). This form sets both registers.

Some instructions only have a record form (with a period). Always make sure to include the period. For example:

  andi.  r3,r4,7 
  andis. r3,r4,7 
  stwcx. r3,r4,r5