DMAC ACC:P,loc32,*XAR7/++
6-86
DMAC ACC:P,loc32,*XAR7/++
16-Bit Dual Multiply and Accumulate
SYNTAX OPTIONS
OPCODE
OBJMODE
RPT
CYC
DMAC ACC:P,loc32,*XAR7
0101 0110 0100 1011
1100 0111 LLLL LLLL
1
Y
N+2
DMAC ACC:P,loc32,*XAR7++
0101 0110 0100 1011
1000 0111 LLLL LLLL
1
Y
N+2
Operands
ACC:P
Accumulator register (ACC) and product register (P)
loc32
Addressing mode (see Chapter 5)
Note:
The @ACC and @P register addressing modes cannot be used. No illegal
instruction trap will be generated if used (assembler will flag an error).
*XAR7 /++
Indirect program-memory addressing using auxiliary register XAR7,
can access full 4M x 16 program space range (0x000000 to 0x3FFFFF)
Description
Dual 16-bit x 16-bit signed multiply and accumulate. The first
multiplication takes place between the upper words of the 32-bit locations
pointed to by the “loc32” and *XAR7/++ addressing modes and second
multiplication takes place with the lower words.
Temp
XT
16
−
bits
VarB_1
VarB_2
XAR7
VarA_1
VarA_2
loc32
VarA_1
VarA_2
VarB_1
VarB_2
VarA_2 * VarB_2 << PM
16
−
bits
ACC
P
VarA_1 * VarB_1 << PM
After the operation the ACC contains the result of multiplying and adding
the upper word of the addressed 32-bit operands. The P register contains
the result of multiplying and adding the lower word of the addressed 32-bit
operands.
XT
= [loc32];
Temp
= Prog[*XAR7 or *XAR7++];
ACC
= ACC + (XT.MSW * Temp.MSW) << PM;
P
= P + (XT.LSW * Temp.LSW) << PM;
Z, N, V, C flags and OVC counter are affected by the operation on ACC
only. The PM shift affects both the ACC and P operations.
On the C28x devices, memory blocks are mapped to both program and
data space (unified memory), hence the ”*XAR7/++” addressing mode
can be used to access data space variables that fall within the program
space address range.
Содержание TMS320C28x
Страница 30: ...1 12...
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Страница 269: ...IN loc16 PA 6 112 MOV AL 0 AL 0 UOUT IORegC AL IOspace IORegC AL 10...
Страница 308: ...MAXCUL P loc32 6 151 Saturate MOVL Var64 2 ACC Store result into Var64 MOVL Var64 P...
Страница 509: ...SUBL ACC P PM 6 352 SUBL ACC P PM ACC S B 11 M X 4 MOVH Y ACC 5 Store Q15 result into Y...
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