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502 lines
21 KiB
C
502 lines
21 KiB
C
//============================================================================
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// QP/C Real-Time Embedded Framework (RTEF)
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// Version 8.0.2
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//
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// Copyright (C) 2005 Quantum Leaps, LLC. All rights reserved.
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//
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// Q u a n t u m L e a P s
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// ------------------------
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// Modern Embedded Software
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//
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// SPDX-License-Identifier: GPL-3.0-or-later OR LicenseRef-QL-commercial
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//
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// This software is dual-licensed under the terms of the open-source GNU
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// General Public License (GPL) or under the terms of one of the closed-
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// source Quantum Leaps commercial licenses.
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//
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// Redistributions in source code must retain this top-level comment block.
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// Plagiarizing this software to sidestep the license obligations is illegal.
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//
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// NOTE:
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// The GPL does NOT permit the incorporation of this code into proprietary
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// programs. Please contact Quantum Leaps for commercial licensing options,
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// which expressly supersede the GPL and are designed explicitly for
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// closed-source distribution.
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//
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// Quantum Leaps contact information:
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// <www.state-machine.com/licensing>
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// <info@state-machine.com>
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//============================================================================
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#define QP_IMPL 1U
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#include "qp_port.h"
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#include "qsafe.h" // QP Functional Safety (FuSa) Subsystem
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// prototypes ----------------------------------------------------------------
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void PendSV_Handler(void);
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#ifdef QK_USE_IRQ_HANDLER // if use IRQ...
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void QK_USE_IRQ_HANDLER(void);
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#else // use default (NMI)
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void NMI_Handler(void);
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#endif
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#define SCB_SYSPRI ((uint32_t volatile *)0xE000ED18U)
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#define NVIC_EN ((uint32_t volatile *)0xE000E100U)
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#define NVIC_IP ((uint32_t volatile *)0xE000E400U)
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#define SCB_CPACR *((uint32_t volatile *)0xE000ED88U)
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#define FPU_FPCCR *((uint32_t volatile *)0xE000EF34U)
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#define NVIC_PEND 0xE000E200
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#define SCB_ICSR 0xE000ED04
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// helper macros to "stringify" values
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#define VAL(x) #x
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#define STRINGIFY(x) VAL(x)
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//============================================================================
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// interrupts and critical section...
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//
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// NOTE:
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// The following interrupt disabling/enabling as well as critical section
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// entry/exit functions are defined as "weak" so that they can be
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// re-implemented differently at the application level.
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//
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// NOTE:
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// For best performance, these functions are implemented in assembly,
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// but they can be implemented in C as well.
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#pragma weak QF_int_disable_
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#pragma weak QF_int_enable_
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#pragma weak QF_crit_entry_
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#pragma weak QF_crit_exit_
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//int32_t volatile QF_int_lock_nest_; // not used
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extern char const QF_port_module_[];
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char const QF_port_module_[] = "qk_port";
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//............................................................................
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// Unconditionally disable interrupts.
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// NOTE: this function must NOT use the stack.
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//
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// Description:
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// When QF_USE_BASEPRI is defined, interrupts are disabled with BASEPRI.
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// Otherwise interrupts are disabled with the PRIMASK register.
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// Additionally, the function also asserts that the interrupts are
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// NOT disabled upon the entry to the function, which means that
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// this interrupt management policy CANNOT nest.
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__stackless
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void QF_int_disable_(void) {
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__asm volatile (
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#ifdef QF_USE_BASEPRI //--------- use BASEPRI for interrupt disabling?
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" MRS r0,BASEPRI \n" // r0 <- previous BASEPRI
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" MOVS r1,#" STRINGIFY(QF_USE_BASEPRI) "\n"
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" MSR BASEPRI,r1 \n" // NOTE: Cortes-M7 erratum 837070 is OK
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#else //--------- use PRIMASK for disabling interrupts
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" MRS r0,PRIMASK \n" // r0 <- previous PRIMASK
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" CPSID i \n" // set PRIMASK
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#endif //--------- use PRIMASK for disabling interrupts
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" CMP r0,#0 \n" // assert(PRIMASK/BASEPRI == 0)
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" BNE QF_int_disable_error\n"
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" BX lr \n"
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"QF_int_disable_error: \n"
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" LDR r0,=QF_port_module_ \n"
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" MOVS r1,#100 \n"
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" LDR r2,=Q_onError \n"
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" BX r2 \n"
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);
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}
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//............................................................................
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// Unconditionally enable interrupts.
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// NOTE: this function must NOT use the stack.
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//
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// Description:
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// When QF_USE_BASEPRI is defined, interrupts are enabled with BASEPRI.
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// Otherwise interrupts are enabled with the PRIMASK register.
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// Additionally, the function also asserts that the interrupts ARE
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// disabled upon the entry to the function, which means that
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// this interrupt management policy CANNOT nest.
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__stackless
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void QF_int_enable_(void) {
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__asm volatile (
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#ifdef QF_USE_BASEPRI //--------- use BASEPRI for enabling interrupts?
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" MRS r0,BASEPRI \n" // r0 <- previous BASEPRI
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#else //--------- use PRIMASK for enabling interrupts
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" MRS r0,PRIMASK \n" // r0 <- previous PRIMASK
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#endif //--------- use PRIMASK for enabling interrupts
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" CMP r0,#0 \n" // assert(PRIMASK/BASEPRI != 0)
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" BEQ QF_int_enable_error\n"
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#ifdef QF_USE_BASEPRI //--------- use BASEPRI for enabling interrupts?
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" MOVS r1,#0 \n"
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" MSR BASEPRI,r1 \n" // NOTE: Cortes-M7 erratum 837070 is OK
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#else //--------- use PRIMASK for enabling interrupts
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" CPSIE i \n" // clear PRIMASK
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#endif //--------- use PRIMASK for enabling interrupts
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" BX lr \n"
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"QF_int_enable_error: \n"
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" LDR r0,=QF_port_module_ \n"
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" MOVS r1,#101 \n"
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" LDR r2,=Q_onError \n"
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" BX r2 \n"
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);
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}
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//............................................................................
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// Enter QF critical section.
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// NOTE: this function must NOT use the stack.
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//
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// Description:
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// When QF_USE_BASEPRI is defined, critical section uses BASEPRI.
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// Otherwise, critical section uses the PRIMASK register.
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// Additionally, the function also asserts that the interrupts are
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// NOT disabled upon the entry to the function, which means that
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// this critical section CANNOT nest.
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__stackless
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void QF_crit_entry_(void) {
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__asm volatile (
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#ifdef QF_USE_BASEPRI //--------- use BASEPRI for critical section?
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" MRS r0,BASEPRI \n" // r0 <- previous BASEPRI
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" MOVS r1,#" STRINGIFY(QF_USE_BASEPRI) "\n"
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" MSR BASEPRI,r1 \n" // NOTE: Cortes-M7 erratum 837070 is OK
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#else //--------- use PRIMASK for critical section
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" MRS r0,PRIMASK \n" // r0 <- previous PRIMASK
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" CPSID i \n" // set PRIMASK
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#endif //--------- use PRIMASK for critical section
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" CMP r0,#0 \n" // assert(PRIMASK/BASEPRI == 0)
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" BNE QF_crit_entry_error\n"
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" BX lr \n"
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"QF_crit_entry_error: \n"
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" LDR r0,=QF_port_module_ \n"
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" MOVS r1,#110 \n"
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" LDR r2,=Q_onError \n"
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" BX r2 \n"
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);
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}
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//............................................................................
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// Exit QF critical section.
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// NOTE: this function must NOT use the stack.
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//
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// description:
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// When QF_USE_BASEPRI is defined, critical section uses BASEPRI.
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// Otherwise, critical section uses the PRIMASK register.
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// Additionally, the function also asserts that the interrupts ARE
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// disabled upon the entry to the function, which means that
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// this critical section CANNOT nest.
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__stackless
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void QF_crit_exit_(void) {
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__asm volatile (
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#ifdef QF_USE_BASEPRI //--------- use BASEPRI for critical section?
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" MRS r0,BASEPRI \n" // r0 <- previous BASEPRI
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#else //--------- use PRIMASK for critical section
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" MRS r0,PRIMASK \n" // r0 <- previous PRIMASK
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#endif //--------- use PRIMASK for critical section
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" CMP r0,#0 \n" // assert(PRIMASK/BASEPRI != 0)
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" BEQ QF_crit_exit_error\n"
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#ifdef QF_USE_BASEPRI //--------- use BASEPRI for critical section?
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" MOVS r1,#0 \n"
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" MSR BASEPRI,r1 \n" // NOTE: Cortes-M7 erratum 837070 is OK
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#else //--------- use PRIMASK
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" CPSIE i \n" // clear PRIMASK
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#endif //--------- use PRIMASK
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" BX lr \n"
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"QF_crit_exit_error: \n"
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" LDR r0,=QF_port_module_ \n"
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" MOVS r1,#111 \n"
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" LDR r2,=Q_onError \n"
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" BX r2 \n"
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);
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}
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//============================================================================
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// Initialize the exception priorities and IRQ priorities to safe values.
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//
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// description:
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// On ARMv7-M or higher, this QF port disables interrupts by means of the
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// BASEPRI register. However, this method cannot disable interrupt
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// priority zero, which is the default for all interrupts out of reset.
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// The following code changes the SysTick priority and all IRQ priorities
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// to the safe value QF_USE_BASEPRI, which the QF critical section can disable.
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// This avoids breaching of the QF critical sections in case the
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// application programmer forgets to explicitly set priorities of all
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// "kernel aware" interrupts.
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//
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// NOTE: The IRQ priorities established in QK_init() can be later changed
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// by the application-level code.
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void QK_init(void) {
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#ifdef QF_USE_BASEPRI //--------- use BASEPRI for critical section?
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// SCB_SYSPRI[2]: SysTick
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SCB_SYSPRI[2] = (SCB_SYSPRI[2] | (QF_USE_BASEPRI << 24U));
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// set all 240 possible IRQ priories to QF_USE_BASEPRI...
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for (uint_fast8_t n = 0U; n < (240U/sizeof(uint32_t)); ++n) {
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NVIC_IP[n] = (QF_USE_BASEPRI << 24U) | (QF_USE_BASEPRI << 16U)
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| (QF_USE_BASEPRI << 8U) | QF_USE_BASEPRI;
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}
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#endif //--------- use BASEPRI for critical section
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// SCB_SYSPRI[2]: PendSV set to priority 0xFF (lowest)
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SCB_SYSPRI[2] = (SCB_SYSPRI[2] | (0xFFU << 16U));
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#ifdef QK_USE_IRQ_NUM //--------- QK IRQ specified?
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// The QK port is configured to use a given ARM Cortex-M IRQ #
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// to return to thread mode (default is to use the NMI exception)
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// clear the IRQ priority to 0 (highest)
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NVIC_IP[QK_USE_IRQ_NUM >> 2U] &= ~(0xFFU << (8U*(QK_USE_IRQ_NUM & 3U)));
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// enable the IRQ
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NVIC_EN[QK_USE_IRQ_NUM >> 5U] = (1U << (QK_USE_IRQ_NUM & 0x1FU));
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#endif //--------- QK IRQ specified
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#ifdef __ARM_FP //--------- if VFP available...
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// make sure that the FPU is enabled by setting CP10 & CP11 Full Access
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SCB_CPACR = (SCB_CPACR | ((3UL << 20U) | (3UL << 22U)));
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// FPU automatic state preservation (ASPEN) lazy stacking (LSPEN)
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FPU_FPCCR = (FPU_FPCCR | (1U << 30U) | (1U << 31U));
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#endif //--------- VFP available
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}
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//============================================================================
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// The PendSV exception is used for handling asynchronous preemption in QK.
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// The use of the PendSV exception is the recommended and most efficient
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// method for performing context switches in ARM Cortex-M.
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//
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// The PendSV exception should have the lowest priority in the whole system
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// (0xFF, see QK_init). All other exceptions and interrupts should have higher
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// priority.
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//
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// Also, *all* "kernel aware" ISRs in the QK application must call the
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// QK_ISR_EXIT() macro, which triggers PendSV when it detects a need for
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// a context switch or asynchronous preemption.
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//
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// Due to tail-chaining and its lowest priority, the PendSV exception will be
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// entered immediately after the exit from the *last* nested interrupt (or
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// exception). In QK, this is exactly the time when the QK activator needs to
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// handle the asynchronous preemption.
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__stackless
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void PendSV_Handler(void) {
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__asm volatile (
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" PUSH {r0,lr} \n" // save stack-aligner + EXC_RETURN
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//<<<<<<<<<<<<<<<<<<<<<<< CRITICAL SECTION BEGIN <<<<<<<<<<<<<<<<<<<<<<<<
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" LDR r0,=QF_int_disable_ \n"
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" BLX r0 \n" // call QF_int_disable_()
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#ifdef QF_MEM_ISOLATE
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" LDR r0,=QF_onMemSys \n"
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" BLX r0 \n" // call QF_onMemSys()
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#endif
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// The PendSV exception handler can be preempted by an interrupt,
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// which might pend PendSV exception again. The following write to
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// ICSR[27] un-pends any such spurious instance of PendSV.
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" LDR r2,=" STRINGIFY(SCB_ICSR) "\n" // Interrupt Control and State
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" MOVS r1,#1 \n"
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" LSLS r1,r1,#27 \n" // r1 := (1 << 27) (UNPENDSVSET bit)
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" STR r1,[r2] \n" // ICSR[27] := 1 (unpend PendSV)
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// The QK activator must be called in a Thread mode, while this code
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// executes in the Handler mode of the PendSV exception. The switch
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// to the Thread mode is accomplished by returning from PendSV using
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// a fabricated exception stack frame, where the return address is
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// QK_activate_().
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//
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// NOTE: the QK activator is called with interrupts DISABLED and also
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// returns with interrupts DISABLED.
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" LSRS r3,r1,#3 \n" // r3 := (r1 >> 3), set T bit (new xpsr)
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" LDR r2,=QK_activate_ \n" // address of QK_activate_
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" SUBS r2,r2,#1 \n" // align Thumb-address at halfword (new pc)
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" LDR r1,=QK_thread_ret \n" // return address after the call (new lr)
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" SUB sp,sp,#8*4 \n" // reserve space for exception stack frame
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" ADD r0,sp,#5*4 \n" // r0 := 5 registers below the SP
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" STM r0!,{r1-r3} \n" // save xpsr,pc,lr
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" MOVS r0,#6 \n"
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" MVNS r0,r0 \n" // r0 := ~6 == 0xFFFFFFF9
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#if (__ARM_ARCH != 6) //--------- if ARMv7-M and higher...
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" DSB \n" // ARM Erratum 838869
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#endif //--------- ARMv7-M and higher
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" BX r0 \n" // exception-return to the QK activator
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);
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}
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//============================================================================
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// QK_thread_ret is a helper function executed when the QXK activator returns.
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//
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// After the QK activator returns, we need to resume the preempted
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// thread. However, this must be accomplished by a return-from-exception,
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// while we are still in the *thread* context. The switching to the
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// exception context is accomplished by triggering the NMI exception or
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// the selected IRQ (if macro #QK_USE_IRQ_NUM is defined).
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//
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// NOTE: QK_thread_ret is entered with interrupts DISABLED.
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// NOTE: any function calls made from this code corrupt lr, but it is
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// NOT used to return from QK_thread_ret(). Instead QK_thread_ret()
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// "returns" by entering an exception (either NMI or IRQ).
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//
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__stackless
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void QK_thread_ret(void) {
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__asm volatile (
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#ifdef QF_MEM_ISOLATE
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" LDR r0,=QF_onMemApp \n"
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" BLX r0 \n" // call QF_onMemApp()
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#endif
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#if (__ARM_ARCH == 6) //--------- if ARMv6-M...
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#ifdef QK_USE_IRQ_NUM //--------- IRQ defined, use the specified IRQ
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" LDR r0,=" STRINGIFY(NVIC_PEND + ((QK_USE_IRQ_NUM >> 5) << 2)) "\n"
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" MOVS r1,#1 \n"
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" LSLS r1,r1,#" STRINGIFY(QK_USE_IRQ_NUM & 0x1F) "\n" // r1 := IRQ bit
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" STR r1,[r0] \n" // pend the IRQ
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" LDR r0,=QF_int_enable_ \n"
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" BLX r0 \n" // enable interrupts with PRIMASK
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// This code stops here and continues in the IRQ handler
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#else //--------- use the NMI (default)
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" LDR r0,=" STRINGIFY(SCB_ICSR) "\n" // Interrupt Control and State
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" MOVS r1,#1 \n"
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" LSLS r1,r1,#31 \n" // r1 := (1 << 31) (NMI bit)
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" STR r1,[r0] \n" // ICSR[31] := 1 (pend NMI)
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// This code stops here and continues in the NMI handler
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// NOTE: interrupts remain *disabled*.
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#endif //--------- use the NMI
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#else //--------- ARMv7-M and higher...
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#ifdef QF_USE_BASEPRI //--------- QF_USE_BASEPRI
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" CPSID i \n" // disable interrupts with PRIMASK
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" LDR r0,=QF_int_enable_ \n"
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" BLX r0 \n" // enable interrupts with BASEPRI
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#endif //--------- QF_USE_BASEPRI
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// NOTE: interrupts remain disabled with PRIMASK
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#ifdef __ARM_FP //--------- if VFP available...
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// make sure that the following IRQ/NMI will NOT use the VFP stack frame
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" MRS r0,CONTROL \n" // r0 := CONTROL
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" BICS r0,r0,#4 \n" // r0 := r0 & ~4 (FPCA bit)
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" MSR CONTROL,r0 \n" // CONTROL := r0 (clear CONTROL[2] FPCA bit)
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" ISB \n" // ISB after MSR CONTROL (ARM AN321,Sect.4.16)
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#endif //--------- VFP available
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#ifdef QK_USE_IRQ_NUM //--------- IRQ defined, use the specified IRQ
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" LDR r0,=" STRINGIFY(NVIC_PEND + ((QK_USE_IRQ_NUM >> 5) << 2)) "\n"
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" MOVS r1,#1 \n"
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" LSLS r1,r1,#" STRINGIFY(QK_USE_IRQ_NUM & 0x1F) "\n" // r1 := IRQ bit
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" STR r1,[r0] \n" // pend the IRQ
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#ifdef QF_USE_BASEPRI //--------- QF_USE_BASEPRI
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" CPSIE i \n" // enable interrupts with PRIMASK
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#else //--------- interrupt disabling with PRIMASK
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" LDR r0,=QF_int_enable_ \n"
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" BLX r0 \n" // enable interrupts with BASEPRI
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#endif //--------- interrupt disabling with PRIMASK
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// This code stops here and continues in the IRQ handler
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#else //--------- use the NMI (default)
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" LDR r0,=" STRINGIFY(SCB_ICSR) "\n" // Interrupt Control and State
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" MOVS r1,#1 \n"
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" LSLS r1,r1,#31 \n" // r1 := (1 << 31) (NMI bit)
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" STR r1,[r0] \n" // ICSR[31] := 1 (pend NMI)
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// NOTE: this code stops here and continues in the NMI handler
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// NOTE: PRIMASK remains *disabled*.
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#endif //--------- use the NMI
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#endif //--------- ARMv7-M and higher
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// execution should *never* reach here, so the following code
|
|
// enters the Q_onError() error handler
|
|
" LDR r0,=QF_int_disable_ \n"
|
|
" BLX r0 \n" // call QF_int_disable_()
|
|
" LDR r0,=QF_port_module_ \n"
|
|
" MOVS r1,#121 \n"
|
|
" LDR r2,=Q_onError \n"
|
|
" BX r2 \n"
|
|
);
|
|
}
|
|
|
|
//============================================================================
|
|
// The following exception handlers are used for returning back to the
|
|
// preempted *thread* context.
|
|
|
|
#ifdef QK_USE_IRQ_NUM //--------- IRQ defined, use the specified IRQ
|
|
|
|
// NOTE: The IRQ Handler is entered with interrupts already ENABLED
|
|
__stackless
|
|
void QK_USE_IRQ_HANDLER(void) {
|
|
__asm volatile (
|
|
" ADD sp,sp,#(8*4) \n" // remove one 8-register exception frame
|
|
" POP {r0,pc} \n" // pop stack aligner and EXC_RETURN to pc
|
|
// NOTE: this causes exception-return to the preempted *thread* context
|
|
);
|
|
}
|
|
|
|
#else //--------- IRQ NOT defined, use the NMI (default)
|
|
|
|
// NOTE: The NMI_Handler() is entered with interrupts still DISABLED!
|
|
__stackless
|
|
void NMI_Handler(void) {
|
|
__asm volatile (
|
|
" ADD sp,sp,#(8*4) \n" // remove one 8-register exception frame
|
|
|
|
#ifdef QF_USE_BASEPRI //--------- QF_USE_BASEPRI
|
|
// NOTE: QF_int_enable_() already called
|
|
" CPSIE i \n" // enable interrupts with PRIMASK
|
|
#else //--------- interrupt disabling with PRIMASK
|
|
" LDR r0,=QF_int_enable_ \n"
|
|
" BLX r0 \n" // enable interrupts with PRIMASK
|
|
|
|
// NOTE: calling QF_int_enable_() corrupted the lr (EXC_RETURN), but
|
|
// it is NOT used to used to return from the exception. (See POP {r0,pc})
|
|
#endif //--------- interrupt disabling with PRIMASK
|
|
" POP {r0,pc} \n" // pop stack aligner and EXC_RETURN to pc
|
|
);
|
|
// NOTE: this causes exception-return to the preempted *thread* context
|
|
}
|
|
|
|
#endif //--------- use the NMI
|
|
|
|
//============================================================================
|
|
#if (__ARM_ARCH == 6) // if ARMv6-M...
|
|
|
|
// hand-optimized quick LOG2 in assembly (no CLZ instruction in ARMv6-M)
|
|
__stackless
|
|
uint_fast8_t QF_qlog2(uint32_t x) {
|
|
static uint8_t const log2LUT[16] = {
|
|
0U, 1U, 2U, 2U, 3U, 3U, 3U, 3U,
|
|
4U, 4U, 4U, 4U, 4U, 4U, 4U, 4U
|
|
};
|
|
uint_fast8_t n;
|
|
|
|
__asm volatile (
|
|
" MOVS %[n],#0 \n"
|
|
#if (QF_MAX_ACTIVE > 16U)
|
|
" LSRS r2,r0,#16 \n"
|
|
" BEQ QF_qlog2_1 \n"
|
|
" MOVS %[n],#16 \n"
|
|
" MOVS r0,r2 \n"
|
|
"QF_qlog2_1: \n"
|
|
#endif
|
|
#if (QF_MAX_ACTIVE > 8U)
|
|
" LSRS r2,r0,#8 \n"
|
|
" BEQ QF_qlog2_2 \n"
|
|
" ADDS %[n],%[n],#8 \n"
|
|
" MOVS r0,r2 \n"
|
|
"QF_qlog2_2: \n"
|
|
#endif
|
|
" LSRS r2,r0,#4 \n"
|
|
" BEQ.N QF_qlog2_3 \n"
|
|
" ADDS %[n],%[n],#4 \n"
|
|
" MOVS r0,r2 \n"
|
|
"QF_qlog2_3:" : [n]"=r"(n)
|
|
);
|
|
return n + log2LUT[x];
|
|
}
|
|
|
|
#endif // ARMv6-M
|
|
|