MPC563XM Reference Manual, Rev. 1
Freescale Semiconductor
909
Preliminary—Subject to Change Without Notice
23.4.9.4.3
Dispatch Microoperation
Dispatch microoperation is an unconditional branch where the target address is always PC+P[31:24]
(unsigned). Dispatch is affected by FLS field (refer to
Section 23.4.9.4.5, “Flush Pipeline
”). Dispatch
microoperation is defined by R/D field (2 bits,
). Field R/D can also be used to define return
Section 23.4.9.4.4, “Return From Subroutine
23.4.9.4.4
Return From Subroutine
When a subroutine
call
or a
dispatch call
microoperation is executed, the return address is saved in RAR
register. To return from a subroutine a microoperation is available to load the contents of RAR register
back to the PC. Fields R/D (2 bits) or RTN (1 bit,
) can be used to return from subroutine. For
R/D field, see
.
Return from subroutine microoperation is affected by FLS (see
Section 23.4.9.4.5, “Flush Pipeline
”) when
field R/D is used. Return execution through RTN always flushes the pipeline.
100111
MZ MDU flag
110111
P[27]
101000
TDL1 channel flag
111000
P[28]
101001
TDL2 channel flag
111001
P[29]
101010
MRL1 channel flag
111010
P[30]
101011
MRL2 channel flag
111011
P[31]
101100
LSR channel flag
111100
PSTO channel flag
101101
MB flag MDU flag
111101
PSTI channel flag
101110
FM[1] channel flag
111110
SMLCK semaphore flag
101111
FM[0] channel flag
111111
false
all other values reserved
1
“less than” is a signed comparison, equal to the xor between ALU flags V and N; e.g., 0 < 0xFFFFFF
tests as false ( 0 < -1).
2
“lower equal” is an unsigned comparison, equal to Z or C; e.g., 0 < 0xFFFFFF tests as true.
Table 23-95. Return and Dispatch - R/D
R/D
Meaning
00
return from subroutine (see
Section 23.4.9.4.4, “Return From Subroutine
01
dispatch jump
10
dispatch call
11
don’t change microinstruction flow
Table 23-96. Return from Sub-routine - RTN
RTN
Meaning
0
return with pipeline flush
Table 23-94. Branch Condition Selection - BCC
BCC
Meaning
BCC
Meaning