ADSP-BF53x/BF56x Blackfin Processor Programming Reference
15-51
Arithmetic Operations
Multiply 32-Bit Operands
General Form
dest_reg *= multiplier_register
Syntax
Dreg *= Dreg ; /* 32 x 32 integer multiply (a) */
Syntax Terminology
Dreg
:
R7–0
Instruction Length
In the syntax, comment (a) identifies 16-bit instruction length.
Functional Description
The Multiply 32-Bit Operands instruction multiplies two 32-bit data reg-
isters (
dest_reg
and
multiplier_register)
and saves the product in
dest_reg
. The instruction mimics multiplication in the C language and
effectively performs
Dreg1
= (
Dreg1
*
Dreg2
)
modulo 2
32
. Since the
integer multiply is modulo 2
32
, the result always fits in a 32-bit
dest_reg
,
and overflows are possible but not detected. The overflow flag in the
ASTAT
register is never set.
Users are required to limit input numbers to ensure that the resulting
product does not exceed the 32-bit
dest_reg
capacity. If overflow notifi-
cation is required, users should write their own multiplication macro with
that capability.
Accumulators
A0
and
A1
are unchanged by this instruction.
The Multiply 32-Bit Operands instruction does not implicitly modify the
number in
multiplier_register
.
Содержание ADSP-BF53x Blackfin
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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...