TM4C1236E6PM Datasheet, PDF (148/1234 Pages) Texas Instruments – Tiva Microcontroller

Cortex-M4 Peripherals
Register 65: Auxiliary Control (ACTLR), offset 0x008
Note: This register can only be accessed from privileged mode.
The ACTLR register provides disable bits for IT folding, write buffer use for accesses to the default
memory map, and interruption of multi-cycle instructions. By default, this register is set to provide
optimum performance from the Cortex-M4 processor and does not normally require modification.
Auxiliary Control (ACTLR)
Base 0xE000.E000
Offset 0x008
Type RW, reset 0x0000.0000
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
reserved
Type RO
RO
RO
RO
RO
RO
RO
RO
RO
RO
RO
RO
RO
RO
RO
RO
Reset
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
reserved
DISOOFP DISFPCA
reserved
DISFOLD DISWBUF DISMCYC
Type RO
RO
RO
RO
RO
RO
RW
RW
RO
RO
RO
RO
RO
RW
RW
RW
Reset
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
Bit/Field
31:10
9
8
7:3
2
Name
reserved
DISOOFP
DISFPCA
reserved
DISFOLD
Type
RO
RW
RW
RO
RW
Reset
0x00
0
0
Description
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
Disable Out-Of-Order Floating Point
Disables floating-point instructions completing out of order with respect
to integer instructions.
Disable CONTROL.FPCA
Disable automatic update of the FPCA bit in the CONTROL register.
Important: ^{Two bits control when FPCA can be enabled: the ASPEN}
bit in the Floating-Point Context Control (FPCC)
register and the DISFPCA bit in the Auxiliary Control
(ACTLR) register.
0x00
0
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
Disable IT Folding
Value Description
0 No effect.
1 Disables IT folding.
In some situations, the processor can start executing the first instruction
in an IT block while it is still executing the IT instruction. This behavior
is called IT folding, and improves performance, However, IT folding can
cause jitter in looping. If a task must avoid jitter, set the DISFOLD bit
before executing the task, to disable IT folding.
148
June 12, 2014
Texas Instruments-Production Data