Freescale Semiconductor MPC5200B User Manual
Page 464
Programming Model
MPC5200B Users Guide, Rev. 1
Freescale Semiconductor
13-31
task’s Variable Table is desired. In addition, if a task does not use the last 16 variables, another Variable Table could start immediately after
that task’s increment values, so as to not waste memory.
When the user writes a program, or when the assembler converts the user’s programs, the SDMA engine will use the initialization variables
and constants that the user or processor should have loaded into the Variable Table. The initial index variables in the LCD tells the engine to
allocate space for the resulting variables in the loop registers. The space will be allocated consecutively, so the user knows with which register
each variable will be associated. This is important when the user’s program tries to reference one of these previously allocated variables. Also,
the eight increment variables in positions 24 through 31 of
are preloaded by the processor, as programmed by the user.
Table 13-38. Variable Table per Task
#
Hex
Offset
Contents
Comments
0
00
Loop-Index Variable or Constant 0
These twenty-four
words (32 bits) are
used for constant
operands to the EUs,
for initialization
values, or for a place
to write results
straight to a variable
in this table. These
are typically
preloaded by the
CPU unless you are
writing directly to a
variable.
1
04
Loop-Index Variable or Constant 1
2
08
Loop-Index Variable or Constant 2
3
0c
Loop-Index Variable or Constant 3
4
10
Loop-Index Variable or Constant 4
5
14
Loop-Index Variable or Constant 5
6
18
Loop-Index Variable or Constant 6
7
1c
Loop-Index Variable or Constant 7
8
20
Loop-Index Variable or Constant 8
9
24
Loop-Index Variable or Constant 9
10
28
Loop-Index Variable or Constant 10
11
2c
Loop-Index Variable or Constant 11
12
30
Loop-Index Variable or Constant 12
13
34
Loop-Index Variable or Constant 13
14
38
Loop-Index Variable or Constant 14
15
3c
Loop-Index Variable or Constant 15
16
40
Loop-Index Variable or Constant 16
17
44
Loop-Index Variable or Constant 17
18
48
Loop-Index Variable or Constant 18
19
4c
Loop-Index Variable or Constant 19
20
50
Loop-Index Variable or Constant 20
21
54
Loop-Index Variable or Constant 21
22
58
Loop-Index Variable or Constant 22
23
5c
Loop-Index Variable or Constant 23
24
60
Compare Type[31:29], Reserved[28:16], Increment Variable 0[15:0]
Variables 24 - 31
may be increment
variables of the
format shown to the
left. Any of these
variables may be
used as normal
Loop-Index Variables
or Constants (like
variables 0 - 23)
instead.
25
64
Compare Type[31:29], Reserved[28:16], Increment Variable 1[15:0]
26
68
Compare Type[31:29], Reserved[28:16], Increment Variable 2[15:0]
27
6c
Compare Type[31:29], Reserved[28:16], Increment Variable 3[15:0]
28
70
Compare Type[31:29], Reserved[28:16], Increment Variable 4[15:0]
29
74
Compare Type[31:29], Reserved[28:16], Increment Variable 5[15:0]
30
78
Compare Type[31:29], Reserved[28:16], Increment Variable 6[15:0]
31
7c
Compare Type[31:29], Reserved[28:16], Increment Variable 7[15:0]