Texas Instruments TMS320C28x, Reference Manual

Page: 266 / 695

IMPYXUL P,XT,loc32
6-109
IMPYXUL P,XT,loc32 Signed 32 X Unsigned 32-Bit Multiply (Lower Half)
SYNTAX OPTIONS OPCODE OBJMODE RPT CYC
IMPYXUL P,XT,loc32
0101 0110 0110 0101
0000 0000 LLLL LLLL
1 − 1
Operands P Product register
XT Multiplicand register
loc32 Addressing mode (see Chapter 5)
Description Multiply the signed 32-bit content of the XT register by the unsigned 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:
temp(37:0) = lower_38 bits(signed XT * unsigned [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
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.
Repeat This instruction is not repeatable. If this instruction follows the RPT
instruction, it resets the repeat counter (RPTC) and executes only once.