Simplified Mnemonics for PowerPC Instructions
PowerPC e500 Core Family Reference Manual, Rev. 1
Freescale Semiconductor C-15
C.4.6 Simplified Mnemonics that Incorporate CR Conditions
(Eliminates BO and Replaces BI with crS)
The mnemonics in Table C-18 are variations of the branch-if-condition-true (BO = 12) and
branch-if-condition-false (BO = 4) encodings. Because these instructions do not depend on the
CTR, the true/false conditions specified by BO can be combined with the CR test bit specified by
BI to create a different set of simplified mnemonics that eliminates the BO operand and the portion
of the BI operand (BI[3–4]) that specifies one of the four possible test bits. However, the simplified
mnemonic cannot specify in which of the eight CR fields the test bit falls, so the BI operand is
replaced by a crS operand.
The standard codes shown in Table C-16 are used for the most common combinations of branch
conditions. Note that for ease of programming, these codes include synonyms; for example, less
than or equal (le) and not greater than (ng) achieve the same result.
NOTE
A CR field symbol, cr0–cr7, is used as the first operand after the
simplified mnemonic. If the default, CR0, is used, no crS is necessary,
Table C-16. Standard Coding for Branch Conditions
Code Description Equivalent Bit Tested
lt Less than — LT
le Less than or equal (equivalent to ng) ng GT
eq Equal — EQ
ge Greater than or equal (equivalent to nl) nl LT
gt Greater than — GT
nl Not less than (equivalent to ge) ge LT
ne Not equal — EQ
ng Not greater than (equivalent to le) le GT
so Summary overflow — SO
ns Not summary overflow — SO
un Unordered (after floating-point comparison) — SO
nu Not unordered (after floating-point comparison) — SO
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