Rn = Fdep Rx By Ry|<Bit6>:<Len6> (Se) - Analog Devices ADSP-2106x SHARC User Manual

Shifter
B Compute Operations
Rn = FDEP Rx BY Ry|<bit6>:<len6> (SE)
Syntax:
Rn = FDEP Rx BY Ry (SE)
Rn = FDEP Rx BY <bit6>:<len6> (SE)
Function:
Deposits and sign-extends a field from register Rx to register Rn. The input field
is right-aligned within the fixed-point field of Rx. Its length is determined by the
len6 field in register Ry or by the immediate len6 field in the instruction. The
field is deposited in the fixed-point field of Rn, starting from a bit position
determined by the bit6 field in register Ry or by the immediate bit6 field in the
instruction. The MSBs of Rn are sign-extended by the MSB of the deposited field,
unless the MSB of the deposited field is off-scale left. Bits to the right of the
deposited field are set to 0. The floating-point extension field of Rn (bits 7-0 of the
40-bit word) is set to all 0s. Bit6 and len6 can take values between 0 and 63
inclusive, allowing for deposit of fields ranging in length from 0 to 32 bits into bit
positions ranging from 0 to off-scale left.
39
Ry
39
Rx
len6 = number of bits to take from Rx, starting from LSB of 32-bit field
39
Rn
sign bit extension
bit6 = starting bit position for deposit,
referenced from LSB of 32-bit field
Example:
39 31
|--------|--------|--abcdef|ghijklmn|--------|
39 31
|aaaaaabc|defghijk|lmn00000|00000000| 00000000 |
\----/\--------------/
sign
extension
Status flags:
SZ Is set if the output operand is 0, otherwise cleared
SV Is set if any bits are deposited to the left of the 32-bit fixed-point output
field (i.e., if len6 + bit6 > 32), otherwise cleared
SS Is cleared
B – 66
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19
len6
deposit field
bit6
23 15 7
\---------------/
len6 bits
23 15 7
|
bit position bit6 (from reference point)
13 7 0
bit6
7 0
7 0
reference point
0
Rx
0
Rn