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ucosII 在LM4F中的应用加入浮点运算

  在LM4F上运行uCosII,而且需要使用FPU主话,移植可以参考M4研讨会PPT3_UCOSII在LM4F中的移植与应用( https://www.deyisupport.com/question_answer/f/57/t/5354.aspx  JSW-M4EVB LM4F232H5QD开发板  光盘里有源码),需要修改两个地方就可以使用了,

 1. 使能KEIL 的 FPU和MCU 的FPU

 2. 修改OSTaskStkInit函数,加入浮点堆栈处理, FPSCR,S15~S0总计18*4=72个字节压栈,还有S31~S16总计 16*4=64字节压栈处理

 3. 修改PendSV中断,加入浮点寄存器 S31~S16的压栈和出栈处理


  • 我是这样做的(红色字体部分),但没有成功,程序跑飞。且编译器提示S16~S31  Bad register name symbol,不得已只好注释掉

    请帮忙看看哪里有问题:

    1. 使能KEIL 的 FPU和MCU 的FPU

        Target Option → Floating Point Hardware→Use FPU

        BSP_PreInit()中:

        ROM_FPUEnable();

        ROM_FPULazyStackingEnable();

     2. 修改OSTaskStkInit函数,加入浮点堆栈处理, FPSCR,S15~S0总计18*4=72个字节压栈,还有S31~S16总计 16*4=64字节压栈处理

        OSTaskStkInit()中:

        

    ...
    stk = ptos; /* Load stack pointer */

    /* Registers stacked as if auto-saved on exception */
    // 要使用FPU,需要加入浮点堆栈处理, FPSCR,S15~S0总计18*4=72个字节压栈,还有S31~S16总计 16*4=64字节压栈处理
    #if 1
    *( stk) = (INT32U)0xccuL; /* No Name Register */
    *(--stk) = (INT32U)0xdduL; /* FPSCR */
    *(--stk) = (INT32U)0xAAAAAAAAuL; /* S15 */
    *(--stk) = (INT32U)0xAAAAAAAAuL; /* S14 */
    *(--stk) = (INT32U)0xAAAAAAAAuL; /* S13 */
    *(--stk) = (INT32U)0xAAAAAAAAuL; /* S12 */
    *(--stk) = (INT32U)0xAAAAAAAAuL; /* S11 */
    *(--stk) = (INT32U)0xAAAAAAAAuL; /* S10 */
    *(--stk) = (INT32U)0xAAAAAAAAuL; /* S9 */
    *(--stk) = (INT32U)0xAAAAAAAAuL; /* S8 */
    *(--stk) = (INT32U)0xAAAAAAAAuL; /* S7 */
    *(--stk) = (INT32U)0xAAAAAAAAuL; /* S6 */
    *(--stk) = (INT32U)0xAAAAAAAAuL; /* S5 */
    *(--stk) = (INT32U)0xAAAAAAAAuL; /* S4 */
    *(--stk) = (INT32U)0xAAAAAAAAuL; /* S3 */
    *(--stk) = (INT32U)0xAAAAAAAAuL; /* S2 */
    *(--stk) = (INT32U)0xAAAAAAAAuL; /* S1 */
    *(--stk) = (INT32U)0xAAAAAAAAuL; /* S0 */
    #endif

    *(--stk) = (INT32U)0x01000000uL; /* xPSR */
    *(--stk) = (INT32U)task; /* Entry Point PC */
    *(--stk) = (INT32U)0xFFFFFFFEL; /* R14 (LR) (init value will */
    /* cause fault if ever used) */
    *(--stk) = (INT32U)0x12121212uL; /* R12 */
    *(--stk) = (INT32U)0x03030303uL; /* R3 */
    *(--stk) = (INT32U)0x02020202uL; /* R2 */
    *(--stk) = (INT32U)0x01010101uL; /* R1 */
    *(--stk) = (INT32U)p_arg; /* R0 : argument */

    /* Remaining registers saved on process stack */
    #if 1
    *(--stk) = (INT32U)0xBBBBBBBBuL; /* S31 */
    *(--stk) = (INT32U)0xBBBBBBBBuL; /* S30 */
    *(--stk) = (INT32U)0xBBBBBBBBuL; /* S29 */
    *(--stk) = (INT32U)0xBBBBBBBBuL; /* S28 */
    *(--stk) = (INT32U)0xBBBBBBBBuL; /* S27 */
    *(--stk) = (INT32U)0xBBBBBBBBuL; /* S26 */
    *(--stk) = (INT32U)0xBBBBBBBBuL; /* S25 */
    *(--stk) = (INT32U)0xBBBBBBBBuL; /* S24 */
    *(--stk) = (INT32U)0xBBBBBBBBuL; /* S23 */
    *(--stk) = (INT32U)0xBBBBBBBBuL; /* S22 */
    *(--stk) = (INT32U)0xBBBBBBBBuL; /* S21 */
    *(--stk) = (INT32U)0xBBBBBBBBuL; /* S20 */
    *(--stk) = (INT32U)0xBBBBBBBBuL; /* S19 */
    *(--stk) = (INT32U)0xBBBBBBBBuL; /* S18 */
    *(--stk) = (INT32U)0xBBBBBBBBuL; /* S17 */
    *(--stk) = (INT32U)0xBBBBBBBBuL; /* S16 */
    #endif

    *(--stk) = (INT32U)0x11111111uL; /* R11 */
    *(--stk) = (INT32U)0x10101010uL; /* R10 */

    ...

     3. 修改PendSV中断,加入浮点寄存器 S31~S16的压栈和出栈处理

    OSPendSV
    CPSID I ; Prevent interruption during context switch
    MRS R0, PSP ; PSP is process stack pointer 栈指针
    CBZ R0, OSPendSV_nosave ; 若PSP=0则执行OSPendSV_nosave函数

    ;SUB R0, R0, #0x40 ; Save remaining regs S16-S31 on process stack
    ;MOV R1, R0
    ;STM R1!, {S16-S31}

    SUB R0, R0, #0x20 ; 压栈R4~R11,共8个寄存器,即4字节*8 = 32 = 0x20
    MOV R1, R0
    STM R1!, {R4-R11} ; 压栈

    LDR R1, =OSTCBCur ; R1 = &OSTCBCur
    LDR R1, [R1] ; R1 = *R1 = *OSTCBCur
    STR R0, [R1] ; *R1 = R0 (R0 is SP of process being switched out)

    ; At this point, entire context of process has been saved
    OSPendSV_nosave
    PUSH {R14} ; Save LR exc_return value
    LDR R0, =OSTaskSwHook ; 调用钩子函数OSTaskSwHook();
    BLX R0
    POP {R14} ; 恢复R14

    LDR R0, =OSPrioCur ; 令当前优先级=最高优先级, OSPrioCur = OSPrioHighRdy
    LDR R1, =OSPrioHighRdy
    LDRB R2, [R1]
    STRB R2, [R0]

    LDR R0, =OSTCBCur ; 设置当前TCB指针 OSTCBCur = OSTCBHighRdy;
    LDR R1, =OSTCBHighRdy
    LDR R2, [R1]
    STR R2, [R0]

    LDR R0, [R2] ; R0 is new process SP; SP = OSTCBHighRdy->OSTCBStkPtr;
    MOV R1, R0
    LDM R1!, {R4-R11} ; Restore r4-11 from new process stack
    ADDS R0, R0, #0x20 ; R4~R11 Regirst

    ;VLDM R0, {S16-S31} ; Restore S16-S31 from new process stack
    ;ADDS R0, R0, #0x40

    MSR PSP, R0 ; PSP=R0, Load PSP with new process SP
    ORR LR, LR, #0x04 ; 确保LR<2>=1,返回到使用进程堆栈
    CPSIE I ; 开中断
    BX LR ; Exception return will restore remaining context