os_cpu_a.asm

这是一个UCOS的AVR移植程序

;********************************************************************************************************
;                                               uC/OS-II
;                                         The Real-Time Kernel
;
;                                          AVR Specific code
;                                           (AVR-GCC 3.x)
;
;
; File         : OS_CPU_A.ASM
; By           : Ole Saether
; Port Version : V1.01
;
; AVR-GCC port version : 1.0 	2001-04-02 modified/ported to avr-gcc by Jesper Hansen ([e-mail])
;
; Modifications by Julius Luukko 2003-02-19 ([e-mail]):
;
; - Minor modification to OSTickISR's declaration to global and addition of #include <avr/io.h> 
;   in order to work with gcc 3.3.
; - Moved 'sei' from the beginning of OSTickISR after the increasing of OSIntNesting (as the book suggests)
; - Changed the order of reloading the timer counter and calling of OSIntExit
; - Changed OSIntCtxSw to the way it is supposed to be with OS_VERSION >= 251
; - Changed OSTickISR so that is saves the stack pointer into the current task's OS_TCB if OSTickISR is the
;   first level ISR
; - os_cfg.h must be included (definitions of CPU_CLOCK_HZ and OS_TICKS_PER_SEC)
; - avr/io.h is included to get SIG_OVERFLOW0 to produce the code to the interrupt vector table
;
; Modifications by Julius Luukko 2003-03-06 ([e-mail]):
;
; - RAMPZ is also saved to the stack
;
; Modifications by Julius Luukko 2003-03-18 ([e-mail]):
;
; - RAMPZ and SREG were popped out of the stack in the wrong order! Corrected this.
; - Divided macros PUSHRS and POPRS into to macros PUSHRS, PUSHSREG, POPRS and POPSREG. Additionally, 
; in ISRs macro called PUSHSREGISR must be used. It sets the I bit i SREG, since its always unset, when
; ISR is entered. It must be, however, set to enable interrupts when the task is run again.
; - RCALLs changed to CALLs. This allows the code of called functions to be further away from the calls.
;   (fixes the "relocating truncated to fit" error from the linker)
; 
;
; Modifications by Julius Luukko 2003-03-19 ([e-mail]):
;
; - timer interrupt is changed so that the timer counter register is updated right after _not_first_int
;   (was AFTER the call to OSIntExit!!)
;
; Modifications by Julius Luukko 2003-06-24 ([e-mail]):
;
; - I/O port addressing is now done using the macro _SFR_IO_ADDR from avr-libc and the address
; definitions are removed from here
; - RAMPZ is pushed and popped only if it is defined, i.e. with chips that have it
;
; Modifications by Julius Luukko 2003-07-21 ([e-mail]) for V2.70
;
; - OSTaskSwHook is not called if OS_TASK_SW_HOOK_EN == 0
; - defines typedef to ; so that os_cfg_r.h can be used more easily as a starting point for
;   the application specific os_cfg.h
;
;********************************************************************************************************

;********************************************************************************************************
;                                      C PREPROCESSOR DIRECTIVES
;********************************************************************************************************

#include <avr/io.h>

#define OS_CPU_A
#include "os_cpu.h"
#define typedef	; 
#include "os_cfg.h"

#ifndef OS_TASK_SW_HOOK_EN
#define OS_TASK_SW_HOOK_EN 1
#endif
	
;********************************************************************************************************
;                                          PUBLIC DECLARATIONS
;********************************************************************************************************

                .global OSStartHighRdy
                .global OSCtxSw
                .global OSIntCtxSw
                .global	OSTickISR

;********************************************************************************************************
;                                         EXTERNAL DECLARATIONS
;********************************************************************************************************

                .extern	OSIntExit
                .extern	OSIntNesting
                .extern	OSPrioCur
                .extern	OSPrioHighRdy
                .extern	OSRunning
#if OS_TASK_SW_HOOK_EN > 0
                .extern	OSTaskSwHook
#endif
                .extern	OSTCBCur
                .extern	OSTCBHighRdy
                .extern	OSTimeTick

;********************************************************************************************************
;                                         MACROS
;********************************************************************************************************

; Push all registers and the status register	
.macro	PUSHRS

                push	r0
                push	r1
                push	r2
                push	r3
                push	r4
                push	r5
                push	r6
                push	r7
                push	r8
                push	r9
                push	r10
                push	r11
                push	r12
                push	r13
                push	r14
                push	r15
                push	r16
                push	r17
                push	r18
                push	r19
                push	r20
                push	r21
                push	r22
                push	r23
                push	r24
                push	r25
                push	r26
                push	r27
                push	r28
                push	r29
                push	r30
                push	r31
#ifdef RAMPZ
                in      r16,_SFR_IO_ADDR(RAMPZ)
                push	r16
#endif
.endm

; Pop all registers and the status registers
.macro	POPRS

#ifdef RAMPZ
                pop     r16
                out     _SFR_IO_ADDR(RAMPZ),r16
#endif
                pop     r31
                pop     r30
                pop     r29
                pop     r28
                pop     r27
                pop     r26
                pop     r25
                pop     r24
                pop     r23
                pop     r22
                pop     r21
                pop     r20
                pop     r19
                pop     r18
                pop     r17
                pop     r16
                pop     r15
                pop     r14
                pop     r13
                pop     r12
                pop     r11
                pop     r10
                pop     r9
                pop     r8
                pop     r7
                pop     r6
                pop     r5
                pop     r4
                pop     r3
                pop     r2
                pop     r1
                pop     r0

.endm

.macro	POPSREG

                pop     r16
                out     _SFR_IO_ADDR(SREG),r16

.endm

.macro	PUSHSREG

                in      r16,_SFR_IO_ADDR(SREG)
                push	r16

.endm

.macro	PUSHSREGISR

                in      r16,_SFR_IO_ADDR(SREG)
                sbr     r16,0x80
                push	r16

.endm


                	.text
                	.section	.text
			

;********************************************************************************************************
;                               START HIGHEST PRIORITY TASK READY-TO-RUN
;
; Description : This function is called by OSStart() to start the highest priority task that was created
;               by your application before calling OSStart().
;
; Note(s)     : 1) The (data)stack frame is assumed to look as follows:
;
;                  OSTCBHighRdy->OSTCBStkPtr --> LSB of (return) stack pointer           (Low memory)
;                                                SPH of (return) stack pointer
;                                                Flags to load in status register
;                                                R31
;                                                R30
;                                                R7