Add full automotive RTOS project

Add kernel (Cortex-M0/M3/M4, Tricore, S32K, RISC-V ports), drivers,
middleware (CAN stack, diagnostics, safety), applications, board
support, build/test tooling, and documentation.

kernel/arch/arm/cortex-m0/portmacro.h

@@ -0,0 +1,40 @@
+/**
+ * @file portmacro.h
+ * @brief ARM Cortex-M0 specific macros
+ */
+
+#ifndef PORTMACRO_H
+#define PORTMACRO_H
+
+#include <stdint.h>
+
+/* Data Types */
+typedef uint32_t port_stack_type_t;
+typedef uint32_t port_base_type_t;
+
+/* Architecture Constants */
+#define PORT_STACK_GROWTH_DIRECTION    (-1)
+#define PORT_BYTE_ALIGNMENT            8
+#define PORT_MAX_SYSCALL_INTERRUPT_PRIORITY  3
+
+/* Critical Section Macros */
+#define portENTER_CRITICAL()    __disable_irq()
+#define portEXIT_CRITICAL()     __enable_irq()
+
+/* Interrupt Control */
+#define portENABLE_INTERRUPTS()  __enable_irq()
+#define portDISABLE_INTERRUPTS() __disable_irq()
+
+/* Context Switch */
+#define portYIELD()             SCB->ICSR |= SCB_ICSR_PENDSVSET_Msk
+#define portYIELD_FROM_ISR()    SCB->ICSR |= SCB_ICSR_PENDSVSET_Msk
+
+/* Memory Barriers */
+#define portMEMORY_BARRIER()    __asm volatile("DMB")
+#define portSYNC_BARRIER()      __asm volatile("DSB")
+#define portINSTRUCTION_BARRIER() __asm volatile("ISB")
+
+/* NOP */
+#define portNOP()               __asm volatile("NOP")
+
+#endif /* PORTMACRO_H */