Power ISA™ Version 2.03 - Power.org

Version 2.03
Rotate Left Word then AND with Mask
M-form
rlwnm RA,RS,RB,MB,ME (Rc=0)
rlwnm. RA,RS,RB,MB,ME (Rc=1)
23 RS RA RB MB ME Rc
0 6 11 16 21 26 31
n (RB) 59:63
r ROTL 32 ((RS) 32:63 , n)
m MASK(MB+32, ME+32)
RA r & m
The contents of register RS are rotated 32 left the number
of bits specified by (RB) 59:63 . A mask is generated
having 1-bits from bit MB+32 through bit ME+32 and
0-bits elsewhere. The rotated data are ANDed with the
generated mask and the result is placed into register
RA.
Special Registers Altered:
CR0
(if Rc=1)
Extended Mnemonics:
Example of extended mnemonics for Rotate Left Word
then AND with Mask:
Extended:
Equivalent to:
rotlw Rx,Ry,Rz rlwnm Rx,Ry,Rz,0,31
Programming Note
Let RSL represent the low-order 32 bits of register
RS, with the bits numbered from 0 through 31.
rlwnm can be used to extract an n-bit field that
starts at variable bit position b in RSL, right-justified
into the low-order 32 bits of register RA (clearing
the remaining 32-n bits of the low-order 32 bits of
RA), by setting RB 59:63 =b+n, MB=32-n, and
ME=31. It can be used to extract an n-bit field that
starts at variable bit position b in RSL, left-justified
into the low-order 32 bits of register RA (clearing
the remaining 32-n bits of the low-order 32 bits of
RA), by setting RB 59:63 =b, MB = 0, and ME=n-1. It
can be used to rotate the contents of the low-order
32 bits of a register left (right) by variable n bits, by
setting RB 59:63 =n (32-n), MB=0, and ME=31.
For all the uses given above, the high-order 32 bits
of register RA are cleared.
Extended mnemonics are provided for some of
these uses; see Appendix D, “Assembler Extended
Mnemonics” on page 313.
Rotate Left Word Immediate then Mask
Insert
M-form
rlwimi RA,RS,SH,MB,ME (Rc=0)
rlwimi. RA,RS,SH,MB,ME (Rc=1)
20 RS RA SH MB ME Rc
0 6 11 16 21 26 31
n SH
r ROTL 32 ((RS) 32:63 , n)
m MASK(MB+32, ME+32)
RA r&m | (RA)&¬m
The contents of register RS are rotated 32 left SH bits.
A mask is generated having 1-bits from bit MB+32
through bit ME+32 and 0-bits elsewhere. The rotated
data are inserted into register RA under control of the
generated mask.
Special Registers Altered:
CR0
(if Rc=1)
Extended Mnemonics:
Example of extended mnemonics for Rotate Left Word
Immediate then Mask Insert:
Extended:
Equivalent to:
inslwi Rx,Ry,n,b rlwimi Rx,Ry,32-b,b,b+n-1
Programming Note
Let RAL represent the low-order 32 bits of register
RA, with the bits numbered from 0 through 31.
rlwimi can be used to insert an n-bit field that is
left-justified in the low-order 32 bits of register RS,
into RAL starting at bit position b, by setting
SH=32-b, MB=b, and ME=(b+n)-1. It can be used
to insert an n-bit field that is right-justified in the
low-order 32 bits of register RS, into RAL starting at
bit position b, by setting SH=32-(b+n), MB=b, and
ME=(b+n)-1.
Extended mnemonics are provided for both of
these uses; see Appendix D, “Assembler Extended
Mnemonics” on page 313.
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Power ISA -- Book I