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TMS320C55x Rules and Guidelines

5.5.6 Status Bits

The C55xx contains four status registers: ST0, ST1, ST2 and ST3.

ST0 Field Name

Use

Type

ACOV2

Overflow flag for AC2

Scratch (local)

ACOV3

Overflow flag for AC3

Scratch (local)

TC1, TC2

Test control flag

Scratch (local)

C

Carry bit

Scratch (local)

ACOV0

Overflow flag for AC0

Scratch (local)

ACOV1

Overflow flag for AC1

Scratch (local)

DP bits (15 to 7)

Data page pointer

Scratch (local)

The following table gives the attributes for the ST1 register fields.

ST1 Field Name

Use

Type

BRAF

Block repeat active flag

Preserve (local)

CPL=1

Compiler mode bit

Init (local)

XF

External flag

Scratch (local)

HM

Host mode bit

Preserve (local)

INTM

Interrupt Mask

Preserve (global)

M40 = 0

40/32-bit computation control for the D-unit

Init (local)

SATD = 0

Saturation control for D-unit

Init (local)

SXMD = 1

Sign extension mode bit for D-unit

Init (local)

C16 = 0

Dual 16-bit math bit

Init (local)

FRCT = 0

Fractional mode bit

Init (local)

LEAD = 0

Lead bit

Init (local)

T2 bits (0 to 4)

Accumulator shift mode

Scratch (local)

The following table describes the attributes for the ST2 register.

ST2 Field Name

Use

Type

ARMS=0

AR Modifier Switch

Init (local)

XCNA

Conditional Execute Control - Address

Read-only (local)

XCND

Conditional Execute Control - Data

Read-only (local)

DBGM

Debug enable mask bit

Read-only (global)

EALLOW

Emulation access enable bit

Read-only (global)

RDM=0

Rounding Mode

Init (local)

CDPLC

Linear/Circular configuration for the CDP pointer

Preserve (local)

AR7LC to AR0LC

Linear/Circular configuration for the AR7 to AR0

Preserve (local)

 

pointer

 

The following table describes the attributes for the ST3 register.

ST3 Field Name

Use

Type

 

CAFRZ

Cache Freeze

Read-only (global)

 

CAEN

Cache Enable

Read-only (global)

 

CACLR

Cache Clear

Read-only (global)

 

HINT

Host Interrupt

Read-only (global)

 

SPRU352G –June 2005 –Revised February 2007

DSP-Specific Guidelines

55

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Texas Instruments TMS320 DSP manual Status Bits, ST2 Field Name Use Type, ST3 Field Name Use Type