Nested Interrupt in rt-thread

发布于 2015-09-11 19:02:32 浏览：3746 订阅该版

7 个回答

aozima 2015-09-11

调网络不抓包，调I2C等时序不上逻辑分析仪，就像电工不用万用表！多用整理的好的文字，比截图更省流量，还能在整理过程中思考。

wade123 2015-09-12

这家伙很懒，什么也没写！

bernard 2015-09-12

这家伙很懒，什么也没写！

wade123 2015-09-13

这家伙很懒，什么也没写！

这是ARM的官方文档
[http://infocenter.arm.com/help/index.jsp?topic=/com.arm.doc.faqs/ka13552.html](http://infocenter.arm.com/help/index.js ... 13552.html)

Solution for a re-entrant interrupt handler

```

IRQ_Handler
    SUB     lr, lr, #4                ; Use SRS to save LR_irq and SPSP_irq
    SRSFD   sp!, #0x13                ;   on to the SVC mode stack
    CPS     #0x13                     ; Switch to SVC mode
    PUSH    {r0-r3, r12}              ; Store AAPCS regs on to SVC stack[/color]

MOV     r1, sp
    AND     r1, r1, #4                ; Ensure 8-byte stack alignment…
    SUB     sp, sp, r1                ; …adjust stack as necessary
    PUSH    {r1, lr}                  ; Store adjustment and LR_svc

BL      identify_and_clear_source ; Clear IRQ source
    CPSIE   i                         ; Enable IRQ
    BL      C_irq_handler             ; Branch to 2nd level handler
    CPSID   i                         ; Disable IRQ

POP     {r1, lr}                  ; Restore LR_svc
    ADD     sp, sp, r1                ; Un-adjust stack

POP     {r0-r3, r12}              ; Restore AAPCS registers
    RFEFD   sp!                       ; Return from the SVC mode stack

```

我不是很懂rt-thread为何没切到SVC mode ???