Merge pull request #585 from esp8266/optimistic-yield

Pass timeout to optimistic_yield, add cont_can_yield check

Author: igrr

cores/esp8266/Arduino.h

@@ -38,9 +38,6 @@ extern "C" {
 #include "esp8266_peri.h"
 #include "twi.h"
 
-void yield(void);
-void optimistic_yield(void);
-
 #define HIGH 0x1
 #define LOW  0x0
 
@@ -140,8 +137,8 @@ void timer0_detachInterrupt(void);
 void ets_intr_lock();
 void ets_intr_unlock();
 
-// level (0-15), 
-// level 15 will disable ALL interrupts, 
+// level (0-15),
+// level 15 will disable ALL interrupts,
 // level 0 will disable most software interrupts
 //
 #define xt_disable_interrupts(state, level) __asm__ __volatile__("rsil %0," __STRINGIFY(level) : "=a" (state))
@@ -207,6 +204,9 @@ void detachInterrupt(uint8_t);
 void setup(void);
 void loop(void);
 
+void yield(void);
+void optimistic_yield(uint32_t interval_us);
+
 // Get the bit location within the hardware port of the given virtual pin.
 // This comes from the pins_*.c file for the active board configuration.
 #define digitalPinToPort(pin)       (0)

cores/esp8266/HardwareSerial.cpp

@@ -1,9 +1,9 @@
-/* 
+/*
  HardwareSerial.cpp - esp8266 UART support
 
  Copyright (c) 2014 Ivan Grokhotkov. All rights reserved.
  This file is part of the esp8266 core for Arduino environment.
- 
+
  This library is free software; you can redistribute it and/or
  modify it under the terms of the GNU Lesser General Public
  License as published by the Free Software Foundation; either
@@ -559,7 +559,7 @@ int HardwareSerial::available(void) {
     }
 
     if (!result) {
-        optimistic_yield();
+        optimistic_yield(USD(_uart->uart_nr) / 128);
     }
 
     return result;

cores/esp8266/cont.S

@@ -1,8 +1,8 @@
-/* 
+/*
   cont.S - continuations support for Xtensa call0 ABI
   Copyright (c) 2014 Ivan Grokhotkov. All rights reserved.
   This file is part of the esp8266 core for Arduino environment.
- 
+
   This library is free software; you can redistribute it and/or
   modify it under the terms of the GNU Lesser General Public
   License as published by the Free Software Foundation; either
@@ -18,106 +18,109 @@
   Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
 */
 
-	.text
-	.align	4
-	.literal_position
-	.global	cont_yield
-	.type	cont_yield, @function
+    .text
+    .align    4
+    .literal_position
+    .global   cont_yield
+    .type     cont_yield, @function
 cont_yield:
-	/* a1: sp */
-	/* a2: void* cont_ctx */
-	/* adjust stack and save registers */
-	addi	a1,	a1, -24
-	s32i	a12, a1, 0
-	s32i	a13, a1, 4
-	s32i	a14, a1, 8
-	s32i	a15, a1, 12
-	s32i	a0,  a1, 16
-	s32i	a2,	 a1, 20
+    /* a1: sp */
+    /* a2: void* cont_ctx */
+    /* adjust stack and save registers */
+    addi    a1,  a1, -24
+    s32i    a12, a1, 0
+    s32i    a13, a1, 4
+    s32i    a14, a1, 8
+    s32i    a15, a1, 12
+    s32i    a0,  a1, 16
+    s32i    a2,  a1, 20
 
-	/* &cont_continue -> cont_ctx.pc_yield */
-	movi	a3, cont_continue
-	s32i	a3, a2, 8
-	/* sp -> cont_ctx.sp_yield */
-	s32i	a1, a2, 12
+    /* &cont_continue -> cont_ctx.pc_yield */
+    movi    a3, cont_continue
+    s32i    a3, a2, 8
+    /* sp -> cont_ctx.sp_yield */
+    s32i    a1, a2, 12
 
-	/* a0 <- cont_ctx.pc_ret */
-	l32i	a0, a2, 0
-	/* sp <- cont_ctx.sp_ret */
-	l32i	a1, a2, 4
-	jx  	a0
+    /* a0 <- cont_ctx.pc_ret */
+    l32i    a0, a2, 0
+    /* sp <- cont_ctx.sp_ret */
+    l32i    a1, a2, 4
+    jx      a0
 
 cont_continue:
-	l32i	a12, a1, 0
-	l32i	a13, a1, 4
-	l32i	a14, a1, 8
-	l32i	a15, a1, 12
-	l32i	a0,  a1, 16
-	l32i	a2,	 a1, 20
-	addi	a1,	 a1, 24
-	ret
-	.size	cont_yield, . - cont_yield
+    l32i    a12, a1, 0
+    l32i    a13, a1, 4
+    l32i    a14, a1, 8
+    l32i    a15, a1, 12
+    l32i    a0,  a1, 16
+    l32i    a2,  a1, 20
+    addi    a1,  a1, 24
+    ret
+    .size    cont_yield, . - cont_yield
 
 ////////////////////////////////////////////////////
 
-	.text
-	.align	4
-	.literal_position
-	.global	cont_run
-	.type	cont_run, @function
+    .text
+    .align   4
+    .literal_position
+    .global  cont_run
+    .type    cont_run, @function
 cont_run:
-	/* a1: sp */
-	/* a2: void* cont_ctx */
-	/* a3: void (*pfn) */
+    /* a1: sp */
+    /* a2: void* cont_ctx */
+    /* a3: void (*pfn) */
 
-	/* adjust stack and save registers */
-	addi	a1,  a1, -20
-	s32i	a12, a1, 0
-	s32i	a13, a1, 4
-	s32i	a14, a1, 8
-	s32i	a15, a1, 12
-	s32i	a0,  a1, 16
+    /* adjust stack and save registers */
+    addi    a1,  a1, -20
+    s32i    a12, a1, 0
+    s32i    a13, a1, 4
+    s32i    a14, a1, 8
+    s32i    a15, a1, 12
+    s32i    a0,  a1, 16
 
-	/* cont_ret -> a4 -> cont_ctx.pc_ret*/
-	movi	a4, cont_ret
-	s32i	a4, a2, 0
-	/* sp -> cont_ctx.sp_ret */
-	s32i	a1, a2, 4
+    /* cont_ret -> a4 -> cont_ctx.pc_ret*/
+    movi    a4, cont_ret
+    s32i    a4, a2, 0
+    /* sp -> cont_ctx.sp_ret */
+    s32i    a1, a2, 4
 
-	/* if cont_ctx.pc_yield != 0, goto cont_resume */
-	l32i	a4, a2, 8
-	bnez	a4, cont_resume
-	/* else */
-	/* set new stack*/
-	l32i	a1, a2, 16;
-	/* goto pfn */
-	movi	a0, cont_norm
-	jx   	a3
+    /* if cont_ctx.pc_yield != 0, goto cont_resume */
+    l32i    a4, a2, 8
+    bnez    a4, cont_resume
+    /* else */
+    /* set new stack*/
+    l32i    a1, a2, 16;
+    /* goto pfn */
+    movi    a0, cont_norm
+    jx      a3
 
 cont_resume:
-	/* a1 <- cont_ctx.sp_yield */
-	l32i	a1, a2, 12
-	/* reset yield flag, 0 -> cont_ctx.pc_yield */
-	movi	a3, 0
-	s32i	a3, a2, 8
-	/* jump to saved cont_ctx.pc_yield */
-	movi	a0, cont_ret
-	jx   	a4
+    /* a1 <- cont_ctx.sp_yield */
+    l32i    a1, a2, 12
+    /* reset yield flag, 0 -> cont_ctx.pc_yield */
+    movi    a3, 0
+    s32i    a3, a2, 8
+    /* jump to saved cont_ctx.pc_yield */
+    movi    a0, cont_ret
+    jx       a4
 
 cont_norm:
-	/* calculate pointer to cont_ctx.struct_start from sp */
-	l32i	a2,	a1, 4
-	/* sp <- cont_ctx.sp_ret */
-	l32i	a1, a2, 4
+    /* calculate pointer to cont_ctx.struct_start from sp */
+    l32i    a2,    a1, 4
+    /* sp <- cont_ctx.sp_ret */
+    l32i    a1, a2, 4
+    /* 0 -> cont_ctx.pc_ret */
+    movi    a4, 0
+    s32i    a4, a2, 0
 
 cont_ret:
-	/* restore registers */
-	l32i	a12, a1, 0
-	l32i	a13, a1, 4
-	l32i	a14, a1, 8
-	l32i	a15, a1, 12
-	l32i	a0,  a1, 16
-	/* adjust stack and return */
-	addi	a1,  a1, 20
-	ret
-	.size	cont_run, . - cont_run
+    /* restore registers */
+    l32i    a12, a1, 0
+    l32i    a13, a1, 4
+    l32i    a14, a1, 8
+    l32i    a15, a1, 12
+    l32i    a0,  a1, 16
+    /* adjust stack and return */
+    addi    a1,  a1, 20
+    ret
+    .size   cont_run, . - cont_run

cores/esp8266/cont.h

@@ -1,8 +1,8 @@
-/* 
+/*
  cont.h - continuations support for Xtensa call0 ABI
  Copyright (c) 2014 Ivan Grokhotkov. All rights reserved.
  This file is part of the esp8266 core for Arduino environment.
- 
+
  This library is free software; you can redistribute it and/or
  modify it under the terms of the GNU Lesser General Public
  License as published by the Free Software Foundation; either
@@ -21,6 +21,8 @@
 #ifndef CONT_H_
 #define CONT_H_
 
+#include <stdbool.h>
+
 #ifndef CONT_STACKSIZE
 #define CONT_STACKSIZE 4096
 #endif
@@ -58,4 +60,8 @@ void cont_yield(cont_t*);
 // return 1 if guard bytes were overwritten.
 int cont_check(cont_t* cont);
 
+// Check if yield() may be called. Returns true if we are running inside
+// continuation stack
+bool cont_can_yield(cont_t* cont);
+
 #endif /* CONT_H_ */

cores/esp8266/cont_util.c

@@ -1,8 +1,8 @@
-/* 
+/*
  cont_util.s - continuations support for Xtensa call0 ABI
  Copyright (c) 2014 Ivan Grokhotkov. All rights reserved.
  This file is part of the esp8266 core for Arduino environment.
- 
+
  This library is free software; you can redistribute it and/or
  modify it under the terms of the GNU Lesser General Public
  License as published by the Free Software Foundation; either
@@ -19,6 +19,9 @@
  */
 
 #include "cont.h"
+#include <stddef.h>
+#include "ets_sys.h"
+
 
 #define CONT_STACKGUARD 0xfeefeffe
 
@@ -34,3 +37,8 @@ int cont_check(cont_t* cont) {
 
     return 0;
 }
+
+bool cont_can_yield(cont_t* cont) {
+    return !ETS_INTR_WITHINISR() &&
+           cont->pc_ret != 0 && cont->pc_yield == 0;
+}