![Xilinx Virtex-II Pro PPC405 Скачать руководство пользователя страница 288](http://html1.mh-extra.com/html/xilinx/virtex-ii-pro-ppc405/virtex-ii-pro-ppc405_user-manual_3410279288.webp)
596
March 2002 Release
1-800-255-7778
Virtex-II Pro™ Platform FPGA Documentation
Chapter 11:
Instruction Set
R
cntlzw
Count Leading Zeros Word
Description
The consecutive leading 0 bits in register
r
S are counted and the count is loaded into
register
r
A. This count ranges from 0 through 32, inclusive.
Pseudocode
n
←
0
do while n < 32
if (
r
S)
n
=
1 then leave
n
←
n + 1
(
r
A)
←
n
Registers Altered
•
r
A.
•
CR[CR0]
LT, GT, EQ, SO
if Rc
=
1.
Exceptions
•
None.
Execution of any of the following invalid-instruction forms results in a boundedly-
undefined result rather than a program exception:
•
Reserved bits containing a non-zero value.
Compatibility
This instruction is defined by the PowerPC user instruction-set architecture (UISA). It is
implemented by all PowerPC processors.
cntlzw
r
A,
r
S
(Rc=0)
cntlzw.
r
A,
r
S
(Rc=1)
X Instruction Form
31
r
S
r
A
0
0
0
0
0
26
Rc
0
6
1
1
1
6
2
1
3
1
Содержание Virtex-II Pro PPC405
Страница 1: ...R Volume 2 a PPC405 User Manual Virtex II Pro Platform FPGA Developer s Kit March 2002 Release...
Страница 14: ...322 www xilinx com March 2002 Release 1 800 255 7778 Virtex II Pro Platform FPGA Documentation Preface R...
Страница 252: ...560 www xilinx com March 2002 Release 1 800 255 7778 Virtex II Pro Platform FPGA Documentation R...
Страница 260: ...568 www xilinx com March 2002 Release 1 800 255 7778 Virtex II Pro Platform FPGA Documentation R...
Страница 562: ...870 www xilinx com March 2002 Release 1 800 255 7778 Virtex II Pro Platform FPGA Documentation R...