RISC-V htimedelta CSR Register

Address 0x605Privilege HypervisorAccess HRW / 64-bitHypervisor and virtualization CSRs

htimedelta holds the virtualized time offset.

Related Search Terms

htimedelta CSR htimedelta 0x605 htimedelta time offset 64-bit timer

Bit Overview

Hover for details · Click to jump↗Open Official Manual

bit 3 = only bit 3; bits 12..11 = bits 12 down to 11

MSBLSB

TIMEDELTA63:0RW

Field Map

Understand htimedelta By Bit Fields

1 key fields

63:0

TIMEDELTA

htimedelta virtualized time offset.

TIMEDELTA (bits 63:0) — htimedelta virtualized time offset.

What This Field Controls

- htimedelta virtualized time offset.

Common Values

This field is better understood together with surrounding context than as a fixed memorized enumeration.

↗Open Official Manual

Official Basis & Search Notes

htimedelta is a hypervisor virtual-time offset CSR. It is HS/M-side hypervisor state, not a VS supervisor CSR copy; guest access is governed by the H extension and relevant state-enable, AIA, Sstc, or Smcsrind rules.

htimedelta address, access class, and width are checked against the official CSR tables: 0x605, HRW, 64-bit.

htimedelta/htimedeltah are not compare registers; they provide the guest time offset.

This state is 64-bit; RV32 uses the corresponding high-half CSR for upper bits.

When writing, modify only officially defined fields; handle WARL, WLRL, WPRI, and reserved fields according to the official specification and implementation behavior.

RISC-V Privileged Architecture Manual - CSR table RISC-V Privileged Architecture Manual - Hypervisor extension RISC-V Sstc extension

What To Check First When Reading This CSR

- htimedelta is a Hypervisor-level CSR; its separate address is in the official HRW access class.
- Guest/VS software does not reach this H-level CSR through a supervisor CSR alias; access is controlled by the H extension and relevant optional-extension rules.

Risk Checks Before Writing

- When writing htimedelta, modify only officially defined target fields and preserve WPRI, reserved, and unchanged fields.

Put It Back Into A Real Flow

Confirm the current software is in an M/HS context that may access Hypervisor CSRs.

Confirm that the H, AIA, Sstc, Smstateen, Smcsrind, or other defining extension is implemented.

Read or write only official fields; whether guest-related access succeeds or traps is controlled by the corresponding extension rules and state-enable state.

FAQ

Can htimedelta be accessed through a supervisor CSR alias?

Do not treat htimedelta as a VS CSR copy. It is an H-level CSR; whether guest/VS access to related functionality traps is defined by the H extension and the relevant optional extension.

How is htimedelta related to time?

It provides a guest time offset, not an interrupt compare value.