sctrclr

Supervisor Control Transfer Record (CTR) clear

This instruction is defined by:

Encoding

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Synopsis

When mstateen0.CTR=1, the SCTRCLR instruction performs the following operations:

  • Zeroes all CTR Entry Registers, for all DEPTH values

  • Reset to Zero the optional CTR cycle counter where implemented

    • ctrdata.CC and ctrdata.CCV bit fields.

Any read of ctrsource, ctrtarget, or ctrdata that follows SCTRCLR, such that it precedes the next qualified control transfer, will return the value 0.

Further, the first recorded transfer following SCTRCLR will have ctrdata.CCV=0.

SCTRCLR execution causes an IllegalInstruction exception if:

  • Smctr is not implemented

  • The instruction is executed in S/VS/VU-mode and Ssctr is not implemented, or mstateen0.CTR=0

  • The instruction is executed in U-mode

SCTRCLR execution causes a VirtualInstruciton exception if mstateen0.CTR=1 and:

  • The instruction is executed in VS-mode and hstateen0.CTR=0

  • The instruction is executed in VU-mode

Access

M HS U VS VU

Always

Always

Always

Always

Always

Decode Variables

Execution

  • Pruned, XLEN == 64

  • Original