2-28
SC140 DSP Core Reference Manual
DALU
Figure 2-9 illustrates the use of the fractional multiplication and multiply-accumulate instructions in the
case of a mixed double-precision multiplication of 16-bit by 32-bit signed operands. The “Signed x
Unsigned” operation is used to multiply the signed high portion of one single-precision number with the
unsigned low portion of the other double-precision number. The “Signed x Signed” DMAC operation is
used to multiply-accumulate the two signed high portions of the two signed operands. The TFRx
instruction in parentheses is an optional instruction that is used only in case all 48 bits of the result are
needed. Otherwise, the result is truncated to a 32 bit fraction.
Figure 2-9. Fractional Mixed-Precision Multiplication
2.2.2.8.2 Integer Multi-Precision Arithmetic
A set of DALU operations is provided for integer multi-precision multiplications. When these instructions
are used, the multiplier accepts some combinations of two’s complement signed and unsigned formats.
Both signed and unsigned multi-precision multiplication are supported. Table 2-16 lists these instructions.
Table 2-16. Integer Signed and Unsigned Two’s Complement Multiplication
Instruction
Description
IMPYSU/IMACSU
Integer multiplication and multiply-accumulate with signed x unsigned operands
IMPYUU
Integer multiplication with unsigned x unsigned operands
IMPYHLUU
Integer multiply unsigned x unsigned:
first source from high portion, second from low portion
IMACLHUU
Integer multiply-accumulate unsigned x unsigned:
first source from low portion, second from high portion
48 bits
D3.l
D2.l
D2.h
D2.e
D0.h
D1.h
D1.l
×
=
S Ext
+
D0.h
×
D1.l
D1.h
×
D0.h
Signed
×
Unsigned
Signed
×
Signed
D0,D1,D2
D2,D3)
D0,D1,D2
mpysu
(tfr
dmacss
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Страница 385: ...BMCHG W SC140 DSP Core Reference Manual A 71 u16 iiiiiiiiiiiiiiii 16 bit unsigned immediate data ...
Страница 388: ...A 74 SC140 DSP Core Reference Manual BMCHG W s16 AAAAAAAAAAAAAAAA 16 bit signed SP address offset ...
Страница 391: ...BMCLR SC140 DSP Core Reference Manual A 77 u16 iiiiiiiiiiiiiiii 16 bit unsigned immediate data ...
Страница 454: ...A 140 SC140 DSP Core Reference Manual DECA u5 iiiii 5 bit unsigned immediate data 1 set by the assembler ...
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Страница 592: ...A 278 SC140 DSP Core Reference Manual MOVE L a32 aaaaaaaaaaaaaaaaAAAAAAAAAAAAAAAA 32 bit absolute long address ...
Страница 618: ...A 304 SC140 DSP Core Reference Manual MOVES 4F s15 sssssssssssssss Signed 15 bit offset ...
Страница 638: ...A 324 SC140 DSP Core Reference Manual MPYR ...
Страница 660: ...A 346 SC140 DSP Core Reference Manual OR W s16 AAAAAAAAAAAAAAAA Signed 16 bit SP address offset ...
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