Method and apparatus for correcting an internal call/return stack in a microprocessor that speculatively executes call and return instructions
US6314514A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Mar 18, 1999 |
| Grant date | Nov 6, 2001 |
| Priority date | — |
| Expiry date | Mar 18, 2019 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06F9/4486
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
An apparatus and method for correcting a call/return stack internal to a microprocessor is provided. In the case of a call, the microprocessor pushes the return address onto the internal call/return stack and in the case of a return, the microprocessor pops the return address from the internal call/return stack into the instruction register. However, prior to speculative execution of the call or return, the correction apparatus stores correction information to enable correction of the internal call/return stack. If the conditional branch instruction was mispredicted, the correction apparatus corrects the internal call/return stack based on the correction information previously stored. The correction information is stored in stack memories so that corrections can be made in the reverse order of which the incorrect modifications to the internal call/return stack were made. This enables correction of the internal call/return stack even if multiple call or return instructions have been speculatively executed prior to resolution of the conditional branch.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.