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Debug Support
MCF5272 ColdFire
®
Integrated Microprocessor User’s Manual, Rev. 3
5-28
Freescale Semiconductor
Operand Data:
None
Result Data:
Requested data is returned as either a word or longword. Byte data is returned in
the least-significant byte of a word result. Word results return 16 bits of significant
data; longword results return 32 bits. A value of 0x0001 (with S set) is returned if
a bus error occurs.
5.5.3.3.6
Fill Memory Block (
FILL
)
A
FILL
command is used with the
WRITE
command to access large blocks of memory. An initial
WRITE
is
executed to set up the starting address of the block and to supply the first operand. The
FILL
command
writes subsequent operands. The initial address is incremented by the operand size (1, 2, or 4) and saved
in a temporary register after the memory write. Subsequent
FILL
commands use this address, perform the
write, increment it by the current operand size, and store the updated address in the temporary register.
If an initial
WRITE
is not executed preceding the first
FILL
command, the illegal command response is
returned.
NOTE
The
FILL
command does not check for a valid address—
FILL
is a valid
command only when preceded by another
FILL
, a
NOP
, or a
WRITE
command.
Otherwise, an illegal command response is returned. The
NOP
command can
be used for intercommand padding without corrupting the address pointer.
The size field is examined each time a
FILL
command is processed, allowing the operand size to be altered
dynamically.
Command Formats:
15
12
11
8
7
4
3
0
Byte
0x1
0xC
0x0
0x0
X
X
X
X
X
X
X
X
D[7:0]
Word
0x1
0xC
0x4
0x0
D[15:0]
Longword
0x1
0xC
0x8
0x0
D[31:16]
D[15:0]
Figure 5-27.
FILL
Command Format