NXP Semiconductors MPC5644A, Reference Manual, Page: 933 / 1735

Enhanced Time Processing Unit (eTPU2)
MPC5644A Microcontroller Reference Manual, Rev. 6
Freescale Semiconductor 933
24.5.9.1.7 Semaphore operations
Semaphore lock and free operations are available through eTPU microcode. For more information about
semaphores see
Section 24.5.4.4, Hardware Semaphores . Two microinstruction fields control semaphore
operations: FL (1 bit) and SMPR (2 bits). Serviced channel sees four semaphores, selected by field SMPR.
When freeing a semaphore, the field SMPR has no meaning. This is because only one semaphore can be
locked at a time by each engine, so when freeing a semaphore it is not necessary to specify its number.
NOTE
If microcode tries to lock a semaphore already locked for the same engine,
the semaphore continues locked for the engine and the SMLCK branch
condition resolves as true.
24.5.9.2 ALU/MDU operations
ALU/MDU microoperations mostly comprises two sources, one destination and one operation. The
operation is generally selected through fields ALUOP, ALUOPI or SHF. In formats where there is no
operation selection field (ALUOP, ALUOPI or SHF), the operation performed is always addition;
however, it is possible to perform subtraction, increment or decrement using fields BINV (see
Section 24.5.9.2.4, B-Source inversion ) and CIN (see Section 24.5.9.2.5, Carry-in Control ).
24.5.9.2.1 Source and destination register set selection
Microcode field T4ABS allows selection of a source from either one of two register sets, shown in
Table 24-81 . The same applies to T2ABD, used for ALU destination selection with other two register sets,
as shown in Table 24-82 . Microinstruction fields ABSE and ABDE control the register set selection for
source and destination, respectively, when available at the format. In formats without ABSE/ABDE, the
field T4BBS determines the register sets used by T2ABD and T4ABS, as shown in
Section ,
Microinstructions Without Fields ABSE and ABDE .
Table 24-76. DIOB Post-Increment / Pre-Decrement – STC
STC Meaning
00 Post-Increment of DIOB
01 Pre-Decrement of DIOB
10 No Increment/Decrement (normal access)
11 No SPRAM Access
1
1
Also disables Zero SPRAM operation
Table 24-77. Semaphore operations fields
Field Meaning
FL 0 = free semaphore,
1 = lock semaphore
SMPR semaphore number selector