61 lines
1.5 KiB
C
61 lines
1.5 KiB
C
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/* ESP8266 Xtensa interrupt management functions
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*
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*
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* Part of esp-open-rtos
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* Copyright (C) 2015 Angus Gratton
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* BSD Licensed as described in the file LICENSE
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*/
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#include <esp/interrupts.h>
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_xt_isr isr[16];
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void IRAM _xt_isr_attach(uint8_t i, _xt_isr func)
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{
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isr[i] = func;
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}
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/* This ISR handler is taken directly from the FreeRTOS port and
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probably could use a cleanup.
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*/
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uint16_t IRAM _xt_isr_handler(uint16_t i)
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{
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uint8_t index;
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/* I think this is implementing some kind of interrupt priority or
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short-circuiting an expensive ffs for most common interrupts - ie
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WDT And GPIO are common or high priority, then remaining flags.
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*/
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if (i & (1 << INUM_WDT)) {
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index = INUM_WDT;
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}
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else if (i & (1 << INUM_GPIO)) {
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index = INUM_GPIO;
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}else {
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index = __builtin_ffs(i) - 1;
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if (index == INUM_MAX) {
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/* I don't understand what happens here. INUM_MAX is not
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the highest interrupt number listed (and the isr array
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has 16 entries).
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Clearing that flag and then setting index to
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__builtin_ffs(i)-1 may result in index == 255 if no
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higher flags are set, unless this is guarded against
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somehow by the caller?
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I also don't understand why the code is written like
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this in esp_iot_rtos_sdk instead of just putting the i
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&= line near the top... Probably no good reason?
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*/
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i &= ~(1 << INUM_MAX);
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index = __builtin_ffs(i) - 1;
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}
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}
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_xt_clear_ints(1<<index);
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isr[index]();
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return i & ~(1 << index);
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}
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