11.3.2. Floating-Point Status and Control Register

The FPSCR Register characteristics are:

Purpose

Provides all necessary User level control of the floating-point system.

Usage constraints

All bits described as DNM in Figure 11.3 are reserved for future expansion. These bits must be initialized to zeros. To ensure that these bits are not modified, any code other than initialization code must use read-modify-write techniques when writing to FPSCR. Failure to observe this rule can cause Unpredictable results in future systems.

Configurations

Use this register if the device is configured as a Cortex-R5F processor.

Attributes

Figure 11.3 shows the bit assignments.

Figure 11.3. FPSCR Register bit assignments

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Table 11.5 shows the bit assignments.

Table 11.5. FPSCR Register bit assignments

BitsNameFunction
[31]NSet if comparison produces a less than result, resets to zero
[30]ZSet if comparison produces an equal result, resets to zero
[29]CSet if comparison produces an equal, greater than, or unordered result, resets to zero
[28]VSet if comparison produces an unordered result, resets to zero
[27]QCDo Not Modify (DNM)/Read As Zero (RAZ)
[26]AHPDNM/RAZ
[25]DN

Default NaN mode enable bit:

0 = default NaN mode disabled, this is the reset value

1 = default NaN mode enabled.

[24]FZ

Flush-to-zero mode enable bit:

0 = flush-to-zero mode disabled, this is the reset value

1 = flush-to-zero mode enabled.

[23:22]RMODE

Rounding mode control field:

b00 = round to nearest (RN) mode, this is the reset value

b01 = round towards plus infinity (RP) mode

b10 = round towards minus infinity (RM) mode

b11 = round towards zero (RZ) mode.

[21:20]STRIDEIndicates the vector stride, reset value is 0x0
[19]-DNM
[18:16]LENIndicates the vector length, reset value is 0x0
[15]IDERAZ
[14:13]-DNM
[12]IXERAZ
[11]UFERAZ
[10]OFERAZ
[9]DZERAZ
[8]IOERAZ
[7]IDCInput Subnormal cumulative flag, resets to zero
[6:5]-DNM
[4]IXCInexact cumulative flag, resets to zero
[3]UFCUnderflow cumulative flag, resets to zero
[2]OFCOverflow cumulative flag, resets to zero
[1]DZCDivision by Zero cumulative flag, resets to zero
[0]IOCInvalid Operation cumulative flag, resets to zero

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