diff options
Diffstat (limited to 'ports/xtensa/xcc/src/tx_timer_interrupt.S')
| -rw-r--r-- | ports/xtensa/xcc/src/tx_timer_interrupt.S | 50 |
1 files changed, 21 insertions, 29 deletions
diff --git a/ports/xtensa/xcc/src/tx_timer_interrupt.S b/ports/xtensa/xcc/src/tx_timer_interrupt.S index 7cca247c..d09badde 100644 --- a/ports/xtensa/xcc/src/tx_timer_interrupt.S +++ b/ports/xtensa/xcc/src/tx_timer_interrupt.S @@ -1,10 +1,11 @@ /*************************************************************************** - * Copyright (c) 2024 Microsoft Corporation - * + * Copyright (c) 2024 Microsoft Corporation + * Copyright (c) 2026-present Eclipse ThreadX contributors + * * This program and the accompanying materials are made available under the * terms of the MIT License which is available at * https://opensource.org/licenses/MIT. - * + * * SPDX-License-Identifier: MIT **************************************************************************/ @@ -33,8 +34,8 @@ /**************************************************************************/ /**************************************************************************/ -/** */ -/** ThreadX Component */ +/** */ +/** ThreadX Component */ /** */ /** Timer */ /** */ @@ -49,26 +50,17 @@ .text -/**************************************************************************/ -/* */ -/* DESCRIPTION */ -/* */ -/* This function processes the hardware timer interrupt. This */ -/* processing includes incrementing the system clock and checking for */ -/* time slice and/or timer expiration. If either is found, the */ -/* interrupt context save/restore functions are called along with the */ -/* expiration functions. */ -/* */ -/* RELEASE HISTORY */ -/* */ -/* DATE NAME DESCRIPTION */ -/* */ -/* 12-31-2020 Cadence Design Systems Initial Version 6.1.3 */ -/* 04-25-2022 Scott Larson Modified comments and updated */ -/* function name, */ -/* resulting in version 6.1.11 */ -/* */ -/**************************************************************************/ +/**************************************************************************/ +/* */ +/* DESCRIPTION */ +/* */ +/* This function processes the hardware timer interrupt. This */ +/* processing includes incrementing the system clock and checking for */ +/* time slice and/or timer expiration. If either is found, the */ +/* interrupt context save/restore functions are called along with the */ +/* expiration functions. */ +/* */ +/**************************************************************************/ // VOID _tx_timer_interrupt(VOID) // { @@ -99,13 +91,13 @@ _tx_timer_interrupt: /* Xtensa timers work by comparing a cycle counter with a preset value. - Once the match occurs an interrupt is generated, and the handler has + Once the match occurs an interrupt is generated, and the handler has to set a new cycle count into the comparator. To avoid clock drift due to interrupt latency, the new cycle count is computed from the old, - not the time the interrupt was serviced. However if a timer interrupt + not the time the interrupt was serviced. However if a timer interrupt is ever serviced more than one tick late, it is necessary to process - multiple ticks until the new cycle count is in the future, otherwise - the next timer interrupt would not occur until after the cycle counter + multiple ticks until the new cycle count is in the future, otherwise + the next timer interrupt would not occur until after the cycle counter had wrapped (2^32 cycles later). do { |