ADSP-BF53x/BF56x Blackfin Processor Programming Reference
13-17
Bit Operations
The operation reads the pattern bit field of length L from the scene bit
field, with the pattern LSB located at bit p of the scene. See “Example”,
below, for more.
Boundary Case
If (p + L) > 32: In the zero-extended and sign-extended versions of the
instruction, the architecture assumes that all bits to the left of the
scene_reg
are zero. In such a case, the user is trying to access more bits
than the register actually contains. Consequently, the architecture fills any
undefined bits beyond the MSB of the
scene_reg
with zeros.
The Bit Field Extraction instruction does not modify the contents of the
two source registers. One of the source registers can also serve as
dest_reg
.
Options
The user has the choice of using the (X) syntax to perform sign-extend
extraction or the (Z) syntax to perform zero-extend extraction.
Flags Affected
This instruction affects flags as follows.
•
AZ
is set if result is zero; cleared if nonzero.
•
AN
is set if result is negative; cleared if non-negative.
Table 13-2. Input Register Bit Field Definitions
31................24
23................16
15..................8
7....................0
scene_reg:
1
ssss ssss
ssss ssss
ssss ssss
ssss ssss
pattern_reg:
2
xxxp pppp
xxxL LLLL
1 where s = scene bit field (32 bits)
2 where:
–p = position of pattern bit field LSB in scene_reg (valid range 0 through 31)
–L = length of pattern bit field (valid range 0 through 31)
Содержание ADSP-BF53x Blackfin
Страница 38: ...Conventions xxxviii ADSP BF53x BF56x Blackfin Processor Programming Reference...
Страница 134: ...System Reset and Powerup 3 18 ADSP BF53x BF56x Blackfin Processor Programming Reference...
Страница 324: ...Instruction Overview 7 20 ADSP BF53x BF56x Blackfin Processor Programming Reference...
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Страница 688: ...Instruction Overview 18 48 ADSP BF53x BF56x Blackfin Processor Programming Reference...
Страница 742: ...Instruction Overview 19 54 ADSP BF53x BF56x Blackfin Processor Programming Reference...
Страница 752: ...Examples 20 10 ADSP BF53x BF56x Blackfin Processor Programming Reference...
Страница 780: ...Product Identification Register 21 28 ADSP BF53x BF56x Blackfin Processor Programming Reference...
Страница 790: ...ADSP BF535 Flags A 10 ADSP BF53x BF56x Blackfin Processor Programming Reference...
Страница 800: ...Performance Monitor Registers B 10 ADSP BF53x BF56x Blackfin Processor Programming Reference...
Страница 994: ...Instructions Listed By Operation Code C 194 ADSP BF53x BF56x Blackfin Processor Programming Reference...
Страница 1042: ...Index I 40 ADSP BF53x BF56x Blackfin Processor Programming Reference...