ADSP-BF53x/BF56x Blackfin Processor Programming Reference
15-77
Arithmetic Operations
RND (Round to Half-Word)
General Form
dest_reg = src_reg (RND)
Syntax
Dreg_lo_hi
=
Dreg
(RND) ;
/* round and saturate the source to
16 bits. (b) */
Syntax Terminology
Dreg
:
R7– 0
Dreg_lo_hi
:
R7–0.L
,
R7–0.H
Instruction Length
In the syntax, comment (b) identifies 32-bit instruction length.
Functional Description
The Round to Half-Word instruction rounds a 32-bit, normalized-frac-
tion number into a 16-bit, normalized-fraction number by extracting and
saturating bits 31–16, then discarding bits 15–0. The instruction supports
only biased rounding, which adds a half LSB (in this case, bit 15) before
truncating bits 15–0. The ALU performs the rounding. The
RND_MOD
bit
in the
ASTAT
register has no bearing on the rounding behavior of this
instruction.
Fractional data types such as the operands used in this instruction are
always signed.
See
“Saturation” on page 1-17
for a description of saturation behavior.
See
“Rounding and Truncating” on page 1-19
for a description of round-
ing behavior.
Summary of Contents for ADSP-BF53x Blackfin
Page 38: ...Conventions xxxviii ADSP BF53x BF56x Blackfin Processor Programming Reference...
Page 134: ...System Reset and Powerup 3 18 ADSP BF53x BF56x Blackfin Processor Programming Reference...
Page 324: ...Instruction Overview 7 20 ADSP BF53x BF56x Blackfin Processor Programming Reference...
Page 486: ...Instruction Overview 13 28 ADSP BF53x BF56x Blackfin Processor Programming Reference...
Page 512: ...Instruction Overview 14 26 ADSP BF53x BF56x Blackfin Processor Programming Reference...
Page 604: ...Instruction Overview 15 92 ADSP BF53x BF56x Blackfin Processor Programming Reference...
Page 688: ...Instruction Overview 18 48 ADSP BF53x BF56x Blackfin Processor Programming Reference...
Page 742: ...Instruction Overview 19 54 ADSP BF53x BF56x Blackfin Processor Programming Reference...
Page 752: ...Examples 20 10 ADSP BF53x BF56x Blackfin Processor Programming Reference...
Page 790: ...ADSP BF535 Flags A 10 ADSP BF53x BF56x Blackfin Processor Programming Reference...
Page 800: ...Performance Monitor Registers B 10 ADSP BF53x BF56x Blackfin Processor Programming Reference...
Page 1042: ...Index I 40 ADSP BF53x BF56x Blackfin Processor Programming Reference...