ADSP-BF53x/BF56x Blackfin Processor Programming Reference
13-11
Bit Operations
The operation writes the foreground bit field of length L over the back-
ground bit field with the foreground LSB located at bit p of the
background. See “Example,” below, for more.
Boundary Cases
Consider the following boundary cases.
• Unsigned syntax, L = 0: The architecture copies
backgnd_reg
con-
tents without modification into
dest_reg
. By definition, a
foreground of zero length is transparent.
• Sign-extended, L = 0 and p = 0: This case loads 0x0000 0000 into
dest_reg
. The sign of a zero length, zero position foreground is
zero; therefore, sign-extended is all zeros.
Table 13-1. Input Register Bit Field Definitions
31................24
23................16
15..................8
7....................0
backgnd_reg:
1
bbbb bbbb
bbbb bbbb
bbbb bbbb
bbbb bbbb
foregnd_reg:
2
nnnn nnnn
nnnn nnnn
xxxp pppp
xxxL LLLL
1 where b = background bit field (32 bits)
2 where:
–n = foreground bit field (16 bits); the L field determines the actual number of foreground bits
used.
–p = intended position of foreground bit field LSB in dest_reg (valid range 0 through 31)
–L = length of foreground bit field (valid range 0 through 16)
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 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...