?? os_cpu_c.c
字號:
/*****************************************************************************
|*
|* Copyright (c) 2001 TASKING, Inc.
|*
|* Description:
|*
|* This module implements the processor specific source code
|* for uC/OS-II.
|* To be used for the 8051 family.
|*
****************************************************************************/
/*
* INCLUDE FILES
*/
#include "includes.h"
#if !defined(_CC51)
# error This piece of code only works with TASKING CC51 V6.0r1 or higher
#endif
/*
* EXTERNAL VARIABLES
*/
extern _idat UBYTE _STKSTART[];
#pragma asm
extrn xdata ( _OSTCBCur ) ; OS_TCB * _xdata OSTCBCur;
extrn xdata ( _OSTCBHighRdy ) ; OS_TCB * _xdata OSTCBHighRdy;
extrn xdata ( _OSRunning )
extrn xdata ( _OSPrioCur ) ; OS_TCB * _xdata OSPrioCur;
extrn xdata ( _OSPrioHighRdy ) ; OS_TCB * _xdata OSPrioHighRdy;
extrn data(__SP)
#pragma endasm
/*
* -------------------------------------------------------------------------
* Both the Task stack and the system stack contain
* the OS context in this format:
*
* high addr: SP
* __SP+1 ; TASKING CC51
* __SP ; Virtual Stack Pointer
* R7
* R6
* R5
* R4
* R3
* R2
* R1
* R0
* DPH
* DPL
* B
* ACC
* PSW
* PCH
* PCL
* low addr:
*
* In TCB stack, SP contains the number of bytes
* saved after OS context (i.e. user data in stack)
*/
/*
* -------------------------------------------------------------------------
* Macros
* -------------------------------------------------------------------------
*/
_inline void save_all( void )
{
#pragma asm
; Save current task context
; PCL, PCH have already been pushed by lcall/interrupt
push psw
push acc
push b
push dpl
push dph
push ar0
push ar1
push ar2
push ar3
push ar4
push ar5
push ar6
push ar7
push __SP ; Save CC51 Virtual Stack Pointer
push __SP+1 ;
push sp
#pragma endasm
}
_inline void rest_all( void )
{
#pragma asm
; Restore task context
pop acc ; SP: discard it
pop __SP+1 ; Restore Virtual Stack Pointer
pop __SP ;
pop ar7
pop ar6
pop ar5
pop ar4
pop ar3
pop ar2
pop ar1
pop ar0
pop dph
pop dpl
pop b
pop acc
pop psw
; ret/reti will pop PCH, PCL
#pragma endasm
}
/*****************************************************************************
|*
|* FUNCTION: OSStartHighRdy
|*
|* DESCRIPTION:
|*
|* Start Multitasking
|*
*/
void OSStartHighRdy(void)
{
#pragma asm
mov R6, #1 ; R6 = 1 : use ret at end of routine
; Determine HighRdy Task stack start and size
lcall _?OSTaskSwHook ; Call OSTaskSwHook;
mov DPTR, #_OSRunning
mov A, #1
movx @DPTR, A ; OSRunning = 1
OSStartHighRdy2:
mov DPTR, #_OSTCBHighRdy ; DPTR = pointer to OSTCBHighRdy
movx A, @DPTR
mov R2, A
inc DPTR
movx A, @DPTR
mov R3, A ; R23 = pointer to structure OS_TCB of OSTCBHighRdy
mov DPH, R2
mov DPL, R3 ; DPTR = pointer to structure OS_TCB of OSTCBHighRdy
movx A, @DPTR
mov R2, A
inc DPTR
movx A, @DPTR
mov R3, A ; R23 = pointer to OSTCBHighRdy->StkPtr
mov DPH, R2
mov DPL, R3 ; DPTR = pointer to OSTCBHighRdy->StkPtr (= Task-stack)
movx A, @DPTR
inc A ; A contains SP of Task-stack
clr C
subb A, #LOW(__STKSTART)
mov R4, A ; R4 contains number of bytes to copy
mov A, DPL
clr C
subb A, R4
mov DPL, A
mov A,DPH
subb A, #0
mov DPH, A ; DPTR = bottom of Task-stack
mov R0, #LOW(__STKSTART) ; R0 = bottom of System-stack
OSStartHighRdyCopy: ; Copy Task-stack to System-stack
inc DPTR
inc R0
movx A, @DPTR
mov @R0, A
djnz R4, OSStartHighRdyCopy ; Task-stack is loaded in System-stack
; DPTR contains top of Task-stack
; R0 contains top of system-stack (= SP)
mov SP, R0 ; SP points to top of System-stack
; If R6 = 1 then return with ret, else return with reti
cjne R6, #1, OSStartHighRdyRTI
; Pop all user register from task stack
#pragma endasm
rest_all();
#pragma asm
setb ea ; Enable interrupts again
ret ; Pop PCH,PCL
OSStartHighRdyRTI:
; Pop all user register from task stack
#pragma endasm
rest_all();
#pragma asm
setb ea ; Enable interrupts again
reti ; Pop PCH,PCL and restore the interrupt logic
; as just before the interrupt occurs
#pragma endasm
}
/*****************************************************************************
|*
|* FUNCTION: OSCtxSw
|*
|* DESCRIPTION:
|*
|* Perform a context switch (from task level)
|*
*/
void OSCtxSw(void)
{
save_all(); /* push registers on stack */
#pragma asm
mov R6, #1 ; R6 = 1 : use ret at end of routine
OSCtxSw2:
mov DPTR, #_OSTCBCur ; DPTR = &OSTCBCur
movx A, @DPTR
mov R2, A
inc DPTR
movx A, @DPTR
mov R3, A ; R23 = pointer to structure OS_TCB of OSTCBCur
mov DPH, R2
mov DPL, R3 ; DPTR = pointer to structure OS_TCB of OSTCBCur
movx A, @DPTR
mov R2, A
inc DPTR
movx A, @DPTR
mov R3, A ; R23 = pointer to OSTCBCur->StkPtr
mov DPH, R2
mov DPL, R3 ; DPTR = pointer to OSTCBCur->StkPtr (= Task-stack as last saved)
movx A, @DPTR
inc A ; A contains SP as last saved
clr C
subb A, #LOW(__STKSTART)
mov R4, A ; R4 contains number of bytes on Task-stack
mov A, DPL
clr C
subb A, R4
mov DPL, A
mov A,DPH
subb A, #0
mov DPH, A ; DPTR = bottom of Task-stack
mov R0, #LOW(__STKSTART) ; R0 = bottom of System-stack
mov A, SP
clr C
subb A, R0
mov R4, A ; R4 contains number of bytes on System-stack
OSCtxSwCopy: ; Copy System-stack to Task-stack
inc DPTR
inc R0
mov A, @R0
movx @DPTR, A
djnz R4, OSCtxSwCopy ; System-stack is saved to Task-stack
; DPTR contains top of Task-stack (= SP)
mov R0, DPH
mov R1, DPL ; R01 contains top of Task-stack
mov DPTR, #_OSTCBCur ; DPTR = pointer to OSTCBCur
movx A, @DPTR
mov R2, A
inc DPTR
movx A, @DPTR
mov R3, A ; R23 = pointer to OSTCBCur->StkPtr
mov DPH, R2
mov DPL, R3 ; DPTR = pointer to OSTCBCur->StkPtr
mov A, R0
movx @DPTR, A
inc DPTR
mov A, R1
movx @DPTR, A ; Top of Task-stack saved in OSTCBCur->StkPtr
mov DPTR, #_OSTCBHighRdy ; DPTR = pointer to OSTCBHighRdy
movx A, @DPTR
mov R0, A
inc DPTR
mov R1, A ; R01 = OSTCBHighRdy
mov DPTR, #_OSTCBCur
mov A, R0
movx @DPTR, A
inc DPTR
mov A, R1
movx @DPTR, A ; OSTCBCur = OSTCBHighRdy
lcall _?OSTaskSwHook ; Call OSTaskSwHook;
mov DPTR, #_OSPrioHighRdy ; DPTR = pointer to OSTCBHighRdy
movx A, @DPTR
mov R0, A
inc DPTR
movx A, @DPTR
mov R1, A ; R01 = OSPrioHighRdy
mov DPTR, #_OSPrioCur
mov A, R0
movx @DPTR, A
inc DPTR
mov A, R1
movx @DPTR, A ; OSPrioCur = OSPrioHighRdy
; Load new task: OSTCBCur
;
ljmp OSStartHighRdy2
#pragma endasm
}
/*****************************************************************************
|*
|* FUNCTION: OSIntCtxSw
|*
|* DESCRIPTION:
|*
|* Perform a context switch (from an ISR)
|* Registers already saved by the interrupt routine
|*
*/
void OSIntCtxSw(void)
{
#pragma asm
mov R6, #0 ; R6 = 0 : use reti at end of routine
; Correct stack poiner for:
; - call to OSIntExit (2 bytes)
; - call to OSIntCtxSw (2 bytes)
;
mov a, sp
clr c
subb a, #4
mov sp, a
; From now on it is the same as OSCtxSw:
ljmp OSCtxSw2
#pragma endasm
}
/*****************************************************************************
|*
|* FUNCTION: OSTaskCreate
|*
|* DESCRIPTION:
|*
|* Create a new task
|*
*/
void *OSTaskStkInit( void (*task)(void *pd), void *pdata, void *ptos, INT16U opt)
{
OS_STK * stk;
OS_STK * vstack_ptr;
opt = opt;
stk = (OS_STK *) ptos - 1 - OS_SYS_STACK_SIZE; /* SP increments before push */
vstack_ptr = (OS_STK *) ptos - OS_SYS_STACK_SIZE; /* __SP decrements before push */
/* WARNING: Next code must match with ucos51a.asm */
*stk++ = ((UWORD) task & 0xFF); /* PCL */
*stk++ = ((UWORD) task >> 8); /* PCH */
*stk++ = 0x00; /* PSW */
*stk++ = 0x11; /* ACC */
*stk++ = 0x22; /* B */
*stk++ = 0x33; /* DPL */
*stk++ = 0x44; /* DPH */
*stk++ = 0x55; /* R0 */
*stk++ = 0x66; /* R1 */
*stk++ = 0x77; /* R2 */
*stk++ = 0x88; /* R3 */
*stk++ = 0x99; /* R4 */
*stk++ = 0x00; /* R5 */
*stk++ = ((UWORD) pdata >> 8); /* R6 */
*stk++ = ((UWORD) pdata & 0xFF); /* R7 */
*stk++ = ((UWORD) vstack_ptr >> 8); /* __SP */
*stk++ = ((UWORD) vstack_ptr & 0xFF); /* __SP+1 */
*stk = 0x11 + (UBYTE) _STKSTART; /* SP 0x11 : pushing the SP saves the value */
/* of the SP before the push */
return ((void *) stk);
}
/*****************************************************************************
|*
|* Function: Timer0IntHandler
|*
|* Description:
|*
|* This interrupt function will be called every time Timer 0
|* overflows.
|*
*/
_interrupt(1) _frame(PSW, A, B, DPL, DPH, R0, R1, R2, R3, R4, R5, R6, R7) void Timer0IntHandler( void )
{
/* save additional data:
* virtual stackpointer __SP
* stackpointer SP
*/
#pragma asm
push __SP
push __SP + 1
push SP
#pragma endasm
OSIntEnter();
/* the timer 0 overflow flag is automatically reset by hardware */
/* no auto-reload in mode 1 */
TL0 = 0x00;
TH0 = 0x00;
OSTimeTick();
OSIntExit();
#pragma asm
pop ACC
pop __SP + 1
pop __SP
#pragma endasm
}
#if OS_CPU_HOOKS_EN
/*****************************************************************************
|*
|* FUNCTION: OSTaskCreateHook
|*
|* DESCRIPTION:
|*
|* empty
|*
*/
void OSTaskCreateHook(OS_TCB *ptcb)
{
ptcb = ptcb;
}
#endif /* OS_CPU_HOOKS_EN */
#if OS_CPU_HOOKS_EN
/*****************************************************************************
|*
|* FUNCTION: OSTaskDelHook
|*
|* DESCRIPTION:
|*
|* Empty
|*
*/
{
ptcb = ptcb;
}
#endif /* OS_CPU_HOOKS_EN */
#if OS_CPU_HOOKS_EN
/*****************************************************************************
|*
|* FUNCTION: OSTaskSwHook
|*
|* DESCRIPTION:
|*
|* Empty
|*
*/
void OSTaskSwHook(void)
{
}
#endif /* OS_CPU_HOOKS_EN */
#if OS_CPU_HOOKS_EN
/*****************************************************************************
|*
|* FUNCTION: OSTaskStatHook
|*
|* DESCRIPTION:
|*
|* Empty
|*
*/
void OSTaskStatHook(void)
{
}
#endif /* OS_CPU_HOOKS_EN */
#if OS_CPU_HOOKS_EN
/*****************************************************************************
|*
|* FUNCTION: OSTimeTickHook
|*
|* DESCRIPTION:
|*
|* Empty
|*
*/
void OSTimeTickHook(void)
{
}
#endif /* OS_CPU_HOOKS_EN */
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