ARM Cortex-M4 - Floating-Point Context Control Register; FPCCR Register Bit Assignments

Cortex-M4 Peripherals
ARM DUI 0553A Copyright © 2010 ARM. All rights reserved. 4-49
ID121610 Non-Confidential
4.6.2 Floating-point Context Control Register
The FPCCR register sets or returns FPU control data. See the register summary in Cortex-M4F
floating-point system registers on page 4-48 for its attributes. The bit assignments are:
31 210
Reserved
MONRDY
Reserved
3
BFRDY
LSPEN
ASPEN
MMRDY
HFRDY
THREAD
USER
LSPACT
30 654789
Reserved
29
Table 4-51 FPCCR register bit assignments
Bits Name Function
[31] ASPEN Enables
CONTROL<2> setting on execution of a floating-point instruction. This results in automatic
hardware state preservation and restoration, for floating-point context, on exception entry and
exit.
0 = Disable
CONTROL<2> setting on execution of a floating-point instruction.
1 = Enable CONTROL<2> setting on execution of a floating-point instruction.
[30] LSPEN 0 = Disable automatic lazy state preservation for floating-point context.
1 = Enable automatic lazy state preservation for floating-point context.
[29:9] - Reserved.
[8] MONRDY 0 = DebugMonitor is disabled or priority did not permit setting MON_PEND when the floating-point
stack frame was allocated.
1 = DebugMonitor is enabled and priority permits setting
MON_PEND when the floating-point stack
frame was allocated.
[7] - Reserved.
[6] BFRDY 0 = BusFault is disabled or priority did not permit setting the BusFault handler to the pending
state when the floating-point stack frame was allocated.
1 = BusFault is enabled and priority permitted setting the BusFault handler to the pending state
when the floating-point stack frame was allocated.
[5] MMRDY 0 = MemManage is disabled or priority did not permit setting the MemManage handler to the
pending state when the floating-point stack frame was allocated.
1 = MemManage is enabled and priority permitted setting the MemManage handler to the
pending state when the floating-point stack frame was allocated.
[4] HFRDY 0 = Priority did not permit setting the HardFault handler to the pending state when the
floating-point stack frame was allocated.
1 = Priority permitted setting the HardFault handler to the pending state when the floating-point
stack frame was allocated.
[3] THREAD 0 = Mode was not Thread Mode when the floating-point stack frame was allocated.
1 = Mode was Thread Mode when the floating-point stack frame was allocated.