MOTOROLA
5-22
INSTRUCTION SET
CPU16
REFERENCE MANUAL
5.11 Stop and Wait Instructions
There are two instructions that put the CPU16 in an inactive state. Both require that
either an interrupt or a reset exception occurs before normal execution of instructions
resumes. However, each operates differently.
LPSTOP minimizes microcontroller power consumption. The CPU16 initiates a stop,
but it and other controller modules are deactivated by the microcontroller system inte-
gration module. Reactivation is also handled by the integration module. The interrupt
priority field from the CPU16 condition code register is copied into the integration mod-
ule external bus interface, then the system clock to the processor is stopped. When a
reset or an interrupt of higher priority than the IP value occurs, the integration module
activates the CPU16, and the appropriate exception processing sequence begins.
WAI idles the CPU16, but does not affect operation of other microcontroller modules.
The IP field is not copied to the integration module. System clocks continue to run. The
processor waits until a reset or an interrupt of higher priority than the IP value occurs,
then begins the appropriate exception processing sequence.
Because the system integration module does not restart the CPU16, interrupts are ac-
knowledged more quickly following WAI than following LPSTOP. See
SECTION 9 EX-
CEPTION PROCESSING
for more information.
RMAC
Repeating
Multiply and Accumulate
Signed 16-Bit Fractions
Repeat until (E)
<
0
(AM) + (H)
(I)
AM
Qualified (IX)
IX;
Qualified (IY)
IY;
(M : M + 1)
X
H;
(M : M + 1)
Y
I
(E) – 1
E
(D[15:8])
X MASK
(D[7:0])
Y MASK
(D)
AM[15:0]
(E)
AM[31:16]
AM[32:35] = AM31
(E)
AM[31:16]
$00
AM[15:0]
AM[32:35] = AM31
Rounded (AM)
Temp
If (SM
(EV ; MV))
then Saturation
E
else Temp[31:16]
E
If (SM
(EV ; MV))
then Saturation
E
else AM[31:16]
E
AM[35:32]
IX[3:0]
AM35
IX[15:4]
AM[31:16]
E
AM[15:0]
D
TDMSK
Transfer D to XMSK : YMSK
TEDM
Transfer E and D to AM[31:0]
Sign Extend AM
TEM
Transfer E to AM[31:16]
Sign Extend AM
Clear AM LSB
Transfer AM to E Rounded
TMER
TMET
Transfer AM to E Truncated
TMXED
Transfer AM to IX : E : D
Table 5-30 DSP Summary (Continued)
Mnemonic
Function
Operation
F
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