[fiber] x86_64 support + return from fiber + tests

examples/linux/fiber/main.cpp

@@ -0,0 +1,56 @@
+/*
+ * Copyright (c) 2020, Erik Henriksson
+ *
+ * This file is part of the modm project.
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/.
+ */
+// ----------------------------------------------------------------------------
+
+#include <modm/debug/logger.hpp>
+#include <modm/processing.hpp>
+
+#include <chrono>
+#include <cmath>
+
+using namespace std::chrono_literals;
+
+#define STACK_SIZE 1024
+
+modm_fiber
+void f1() {
+	MODM_LOG_INFO << "f1" << modm::endl;
+	modm::yield();
+	MODM_LOG_INFO << "f1 done" << modm::endl;
+	modm::done();
+}
+
+modm_fiber
+void f2() {
+	MODM_LOG_INFO << "f2" << modm::endl;
+	modm::yield();
+	MODM_LOG_INFO << "f2 done" << modm::endl;
+	modm::done();
+}
+
+modm_fiber
+void idle() {
+	MODM_LOG_INFO << "idle" << modm::endl;
+	modm::yield();
+	MODM_LOG_INFO << "all done" << modm::endl;
+	modm::done();
+}
+
+modm::fiber::Stack<STACK_SIZE> stack1, stack2, stack_idle;
+modm::Fiber fiber1(stack1, &f1), fiber2(stack2, &f2), fiber_idle(stack_idle, &idle);
+
+int main( int argc, char * argv[])
+{
+	MODM_LOG_INFO << "Start" << modm::endl;
+  modm::fiber::scheduler().start();
+  // Will never get here.
+	MODM_LOG_INFO << "End" << modm::endl;
+  return 0;
+}

examples/linux/fiber/project.xml

@@ -0,0 +1,12 @@
+<library>
+  <options>
+    <option name="modm:target">hosted-darwin</option>
+    <option name="modm:build:build.path">../../../build/linux/fiber</option>
+  </options>
+  <modules>
+    <module>modm:debug</module>
+    <module>modm:platform:core</module>
+    <module>modm:processing:fiber</module>
+    <module>modm:build:scons</module>
+  </modules>
+</library>

examples/samd/fiber/main.cpp

@@ -25,16 +25,15 @@ using namespace std::chrono_literals;
 #define STACK_SIZE 40
 #endif
 
-modm_fiber
+
 void f1();
 
-modm_fiber
+
 void f2();
 
 modm::fiber::Stack<STACK_SIZE> stack1, stack2;
 modm::Fiber fiber1(stack1, &f1), fiber2(stack2, &f2);
 
-modm_fiber
 void f1() {
 #ifdef MODM_BOARD_HAS_LOGGER
   MODM_LOG_INFO << "f1: entered" << modm::endl;
@@ -45,7 +44,6 @@ void f1() {
   }
 }
 
-modm_fiber
 void f2() {
 #ifdef MODM_BOARD_HAS_LOGGER
   MODM_LOG_INFO << "f2: entered" << modm::endl;

src/modm/board/blue_pill/board.hpp

@@ -15,6 +15,8 @@
 
 #include <modm/platform.hpp>
 #include <modm/architecture/interface/clock.hpp>
+#include <modm/debug/logger.hpp>
+#define MODM_BOARD_HAS_LOGGER
 
 using namespace modm::platform;
 
@@ -95,12 +97,24 @@ using Leds = SoftwareGpioPort< LedGreen >;
 
 using Button = GpioUnused;
 
+namespace stlink
+{
+using Rx = GpioInputA3;
+using Tx = GpioOutputA2;
+using Uart = Usart2;
+}
+
+using LoggerDevice = modm::IODeviceWrapper< stlink::Uart, modm::IOBuffer::BlockIfFull >;
+
 inline void
 initialize()
 {
 	SystemClock::enable();
 	SysTickTimer::initialize<SystemClock>();
 
+	stlink::Uart::connect<stlink::Tx::Tx, stlink::Rx::Rx>();
+	stlink::Uart::initialize<SystemClock, 115200_Bd>();
+
 	LedGreen::setOutput(modm::Gpio::Low);
 }
 

src/modm/board/blue_pill/module.lb

@@ -60,15 +60,17 @@ def prepare(module, options):
 
     module.depends(
         ":architecture:clock",
+        ":debug",
         ":platform:clock",
         ":platform:core",
-        ":platform:gpio")
+        ":platform:gpio",
+        ":platform:uart:2")
     return True
 
 def build(env):
     env.outbasepath = "modm/src/modm/board"
     env.substitutions = {
-        "with_logger": False,
+        "with_logger": True,
         "with_assert": env.has_module(":architecture:assert")
     }
     env.template("../board.cpp.in", "board.cpp")

src/modm/board/feather_m0/module.lb

@@ -37,8 +37,8 @@ def prepare(module, options):
 def build(env):
     env.outbasepath = "modm/src/modm/board"
     env.substitutions = {
-        "with_logger": False,
-        "with_assert": False,
+        "with_logger": True,
+        "with_assert": True,
     }
     env.template("../board.cpp.in", "board.cpp")
     env.template("board.hpp.in", "board.hpp")

src/modm/processing/fiber/context.cpp

@@ -0,0 +1,15 @@
+/*
+ * Copyright (c) 2020, Erik Henriksson
+ *
+ * This file is part of the modm project.
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/.
+ */
+// ----------------------------------------------------------------------------
+
+
+#include "context.hpp"
+
+modm_context main_context;

src/modm/processing/fiber/context.hpp

@@ -15,33 +15,33 @@
 
 #include <cstddef>
 
-typedef uint32_t modm_stack_t;
+typedef void* modm_stack_t;
 
 struct modm_context {
   modm_stack_t* sp;
   std::size_t stack_size = 0;
 };
 
+extern modm_context main_context;
+
 /* Prepares the stack to look like the "from" arg after modm_jumpcontext as run. */
-extern "C"
 modm_always_inline
 modm_context
-modm_makecontext(modm_stack_t* stack, std::size_t stack_size, void (*fn)(void)) {
-  modm_stack_t* sp = stack + stack_size / sizeof(modm_stack_t) - 1;
-  *sp = (modm_stack_t) fn;
-  return {sp, stack_size};
-}
-
-/* Switches control from the main thread to the user thread. */
-extern "C"
+modm_makecontext(modm_stack_t* stack, std::size_t stack_size, void (*fn)(void), void (*end)(void));
+
+/* Switches control from the main context to the user context. */
 modm_always_inline
 void
 modm_startcontext(const modm_context to);
 
-/* Jumps from the "from" context to the "to" context. */
-extern "C"
+/* Jumps from the "from" user context to the "to" user context. */
 modm_always_inline
 void
 modm_jumpcontext(modm_context* from, const modm_context to);
 
-#include "context_cortex_impl.hpp"
+/* Switches control back to the main context from the user context. */
+modm_always_inline
+void
+modm_endcontext();
+
+#include "context_impl.hpp"

src/modm/processing/fiber/context_cortex_impl.hpp

@@ -9,39 +9,129 @@
  */
 // ----------------------------------------------------------------------------
 
-extern "C"
-modm_always_inline
+#include <modm/platform/device.hpp>
+#include <modm/debug/logger.hpp>
+
+// Stack layout:
+// r8
+// r9
+// r10
+// r11
+// r4
+// r5
+// r6
+// r7
+// LR
+// PC
+
+
+modm_context
+modm_makecontext(modm_stack_t* stack, std::size_t stack_size,
+                 void (*fn)(void), void (*end)(void)) {
+  modm_stack_t* sp = stack + stack_size / sizeof(modm_stack_t);
+  *--sp = (modm_stack_t) fn; // PC
+  *--sp = (modm_stack_t) end; // LR
+  sp -= 8; // r4-r11
+  return {sp, stack_size};
+}
+
 void
 modm_startcontext(const modm_context to) {
+  modm_stack_t** main_sp = &main_context.sp;
   modm_stack_t* to_sp = to.sp;
   asm volatile(
+    "adr r3, 1f\n\t" // Load address of instruction after "pop {pc}" into r3
+    "add r3, r3, #1\n\t" // Stay in thumb mode
+    "push {r3}\n\t" // Save instruction address to stack (to be used for PC later)
+
+    "push {r4-r7, lr}\n\t"
+    "mov r4, r8\n\t"
+    "mov r5, r9\n\t"
+    "mov r6, r10\n\t"
+    "mov r7, r11\n\t"
+    "push {r4-r7}\n\t"
+
+    "mov r3, sp\n\t"
+    "str r3, [%[main_sp]]\n\t" // Store the main SP in "main_sp"
     "msr psp, %[to_sp]\n\t" // Set PSP to top of stack
-    "mrs r1, control\n\t"
+    "mrs r3, control\n\t"
     "mov r2, #0x2\n\t" // Set SPSEL
-    "orr r1, r1, r2\n\t"
-    "msr control, r1\n\t"
+    "orr r3, r2\n\t"
+    "msr control, r3\n\t"
+
+    "pop {r4-r7}\n\t"
+    "mov r8, r4\n\t"
+    "mov r9, r5\n\t"
+    "mov r10, r6\n\t"
+    "mov r11, r7\n\t"
+    "pop {r4-r7}\n\t"
+    "pop {r3}\n\t"
+    "mov lr, r3\n\t"
+
     "pop {pc}\n\t" // Perform the jump
-    /*outputs*/: [to_sp] "+r" (to_sp)
+    ".align 2\n\t"
+    "1:\n\t"
+    /*outputs*/: [main_sp] "+r" (main_sp), [to_sp] "+r" (to_sp)
     /*inputs*/:
-    /*clobbers*/: "r1", "r2", "r3", "r4", "r5", "r6", "r7", "r8", "r9", "r10", "r11", "r12", "r13", "r14", "r15", "memory");
+    /*clobbers*/: "r2", "r3", "memory");
 }
 
-extern "C"
 void
 modm_jumpcontext(modm_context* from, const modm_context to) {
-  modm_stack_t** from_sp = &from->sp;
-  modm_stack_t* to_sp = to.sp;
+  register modm_stack_t** from_sp asm("r0") = &from->sp;
+  register modm_stack_t* to_sp asm("r1") = to.sp;
   asm volatile(
     "adr r3, 1f\n\t" // Load address of instruction after "pop {pc}" into r3
     "add r3, r3, #1\n\t" // Stay in thumb mode
-    "push {r3}\n\t" // Push instruction address to stack (to be used for PC later)
+    "push {r3}\n\t" // Save instruction address to stack (to be used for PC later)
+
+    "push {r4-r7, lr}\n\t"
+    "mov r4, r8\n\t"
+    "mov r5, r9\n\t"
+    "mov r6, r10\n\t"
+    "mov r7, r11\n\t"
+    "push {r4-r7}\n\t"
+
     "mov r3, sp\n\t"
     "str r3, [%[from_sp]]\n\t" // Store the SP in "from"
     "mov sp, %[to_sp]\n\t" // Restore SP from "to"
+
+    "pop {r4-r7}\n\t"
+    "mov r8, r4\n\t"
+    "mov r9, r5\n\t"
+    "mov r10, r6\n\t"
+    "mov r11, r7\n\t"
+    "pop {r4-r7}\n\t"
+    "pop {r3}\n\t"
+    "mov lr, r3\n\t"
+
     "pop {pc}\n\t" // Perform the jump
     ".align 2\n\t"
     "1:\n\t"
     /*outputs*/: [from_sp] "+r" (from_sp), [to_sp] "+r" (to_sp)
     /*inputs*/:
-    /*clobbers*/: "r2", "r3", "r4", "r5", "r6", "r7", "r8", "r9", "r10", "r11", "r12", "r13", "r14", "r15", "memory");
+    /*clobbers*/: "r2", "r3", "r4", "r5", "r6", "r7", "r8", "r9", "r10", "r11", "r12", "memory");
 }
+
+void
+modm_endcontext() {
+  asm volatile(
+    "mrs r1, control\n\t"
+    "mov r2, #0x2\n\t" // Unset SPSEL
+    "bic r1, r1, r2\n\t"
+    "msr control, r1\n\t"
+
+    "pop {r4-r7}\n\t"
+    "mov r8, r4\n\t"
+    "mov r9, r5\n\t"
+    "mov r10, r6\n\t"
+    "mov r11, r7\n\t"
+    "pop {r4-r7}\n\t"
+    "pop {r3}\n\t"
+    "mov lr, r3\n\t"
+
+    "pop {pc}\n\t" // Perform the jump
+    /*outputs*/:
+    /*inputs*/:
+    /*clobbers*/: "r1", "r2", "memory");
+  }