Cortex-A9 Technical Reference ManualRevision: r2p0
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4.2.31. NEON busy Register

The NEON busy Register characteristics are:

Purpose

Enables software to determine if a NEON instruction is executing.

Usage constraints

  • a read-only register in Secure state

  • a read-only register in Non-secure state

Configurations

Available in all configurations.

Attributes

See the register summary in Table 4.27.

Figure 4.15 shows the NEON busy register bit assignments

Figure 4.15. NEON busy register bit assignments


Table 4.29 shows the NEON busy Register bit assignments.

Table 4.29. Neon busy Register bit assignments

BitsNameDescription
[31:1]-Reserved.
[0]NEON busySoftware can use this to determine if a NEON instruction is executing. This bit is set to 1 if there is a NEON instruction in NEON pipeline, or in the core pipeline

To access the NEON busy Register, use:

MRC p15,0,<Rd>,c15,c1,0; Read NEON busy Register
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