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IMPYSL P,XT,loc32
6-107
IMPYSL P
,
XT
,
loc32
Signed 32-Bit Multiply (Low Half) and Subtract P
SYNTAX OPTIONS
OPCODE
OBJMODE
RPT
CYC
IMPYSL P,XT,loc32
0101 0110 0100 0011
0000 0000 LLLL LLLL
1
−
1
Operands
P
Product register
XT
Multiplicand register
loc32
Addressing mode (see Chapter 5)
Description
Subtract the unsigned content of the P register, ignoring the product shift
mode (PM), from the ACC register. Multiply the signed 32-bit content of the
XT register by the signed 32-bit content of the location pointed to by the
“loc32” addressing mode. The product shift mode (PM) then determines
which part of the lower 38 bits of the 64-bit result are stored in the P register:
ACC = ACC - unsigned P;
temp(37:0) = lower_38 bits(signed XT * signed [loc32]);
if( PM = +4 shift )
P(31:4) = temp(27:0), P(3:0) = 0;
if( PM = +1 shift )
P(31:1) = temp(30:0), P(0) = 0;
if( PM = 0 shift )
P(31:0) = temp(31:0);
if( PM = −1 shift )
P(31:0) = temp(32:1);
if( PM = −2 shift )
P(31:0) = temp(33:2);
if( PM = −3 shift )
P(31:0) = temp(34:3);
if( PM = −4 shift )
P(31:0) = temp(35:4);
if( PM = −5 shift )
P(31:0) = temp(36:5);
if( PM = −6 shift )
P(31:0) = temp(37:6);
Flags and
Modes
Z
After the subtraction, the Z flag is set if the ACC value is zero, else Z is
cleared.
N
After the subtraction, the N flag is set if bit 31 of the ACC is 1, else N is
cleared.
C
If the subtraction generates a borrow, C is cleared; otherwise C is set.
V
If an overflow occurs, V is set; otherwise V is not affected.
OVCU
The overflow counter is decremented when the subtraction operation gener-
ates an unsigned borrow. The OVM mode does not affect the OVCU counter.
PM
The value in the PM bits sets the shift mode that determines which portion of
the lower 38 bits of the 64-bit results are stored in the P register.
Summary of Contents for TMS320C28x
Page 30: ...1 12...
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Page 269: ...IN loc16 PA 6 112 MOV AL 0 AL 0 UOUT IORegC AL IOspace IORegC AL 10...
Page 308: ...MAXCUL P loc32 6 151 Saturate MOVL Var64 2 ACC Store result into Var64 MOVL Var64 P...
Page 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...
Page 585: ...This page intentionally left blank 7 32 This page intentionally left blank...