gos_x_threads_cortexm347.h

/*
 * This file is subject to the terms of the GFX License. If a copy of
 * the license was not distributed with this file, you can obtain one at:
 *
 *              http://ugfx.io/license.html
 */
 
/**
 * Thread Switching Functions for the Cortex M3, M4 & M7 without hardware floating point
 *
 * Use the EABI calling standard (ARM's AAPCS) - Save r4 - r11
 * The context is saved at the current stack location and a pointer is maintained in the thread structure.
 */
 
 
#if defined(CORTEX_USE_FPU) && CORTEX_USE_FPU
    #if GFX_COMPILER_WARNING_TYPE == GFX_COMPILER_WARNING_DIRECT
        #warning "GOS Threads: You have specified GFX_CPU=GFX_CPU_CORTX_M? with no hardware floating point support but CORTEX_USE_FPU is GFXON. Try using GFX_CPU_GFX_CPU_CORTEX_M?_FP instead"
    #elif GFX_COMPILER_WARNING_TYPE == GFX_COMPILER_WARNING_MACRO
        COMPILER_WARNING("GOS Threads: You have specified GFX_CPU=GFX_CPU_CORTX_M? with no hardware floating point support but CORTEX_USE_FPU is GFXON. Try using GFX_CPU_GFX_CPU_CORTEX_M?_FP instead")
    #endif
#endif
 
#if GFX_COMPILER == GFX_COMPILER_GCC || GFX_COMPILER == GFX_COMPILER_CYGWIN || GFX_COMPILER == GFX_COMPILER_MINGW32 || GFX_COMPILER == GFX_COMPILER_MINGW64
    #define GFX_THREADS_DONE
    #define _gfxThreadsInit()
 
    static __attribute__((pcs("aapcs"),naked)) void _gfxTaskSwitch(thread *oldt, thread *newt) {
        __asm__ volatile (  "push   {r4, r5, r6, r7, r8, r9, r10, r11, lr}  \n\t"
                            "str    sp, %[oldtcxt]                          \n\t"
                            "ldr    sp, %[newtcxt]                          \n\t"
                            "pop    {r4, r5, r6, r7, r8, r9, r10, r11, pc}  \n\t"
                            : [newtcxt] "=m" (newt->cxt)
                            : [oldtcxt] "m" (oldt->cxt)
                            : "memory");
    }
 
    static __attribute__((pcs("aapcs"),naked)) void _gfxStartThread(thread *oldt, thread *newt) {
        newt->cxt = (void *)(((unsigned)newt + newt->size) & ~7);
        __asm__ volatile (  "push   {r4, r5, r6, r7, r8, r9, r10, r11, lr}  \n\t"
                            "str    sp, %[oldtcxt]                          \n\t"
                            "ldr    sp, %[newtcxt]                          \n\t"
                            : [newtcxt] "=m" (newt->cxt)
                            : [oldtcxt] "m" (oldt->cxt)
                            : "memory");
 
        // Run the users function
        gfxThreadExit(_gfxCurrentThread->fn(_gfxCurrentThread->param));
    }
 
#elif GFX_COMPILER == GFX_COMPILER_KEIL || GFX_COMPILER == GFX_COMPILER_ARMCC
    #define GFX_THREADS_DONE
    #define _gfxThreadsInit()
 
    static __asm void _gfxTaskSwitch(thread *oldt, thread *newt) {
        PRESERVE8
 
        // Save the old context
        push    {r4, r5, r6, r7, r8, r9, r10, r11, lr}
        str sp, [r0,#__cpp(offsetof(thread,cxt))]       // oldt->cxt
        
        // Load the new context
        ldr sp, [r1,#__cpp(offsetof(thread,cxt))]       // newt->cxt
        pop {r4, r5, r6, r7, r8, r9, r10, r11, pc}
    }
 
    static __asm void _gfxStartThread(thread *oldt, thread *newt) {
        PRESERVE8
 
        // Calculate where to generate the new context
        //      newt->cxt = (void *)(((unsigned)newt + newt->size) & ~7);
        ldr      r2,[r1,#__cpp(offsetof(thread,size))]
        add      r2,r2,r1
        and      r2, r2, #0xFFFFFFF8
        str      r2,[r1,#__cpp(offsetof(thread,cxt))]
        
        // Save the old context
        push    {r4, r5, r6, r7, r8, r9, r10, r11, lr}
        str     sp, [r0,#__cpp(offsetof(thread,cxt))]   // oldt->cxt
        
        // Load the new (imcomplete) context
        ldr     sp, [r1,#__cpp(offsetof(thread,cxt))]   // newt->cxt
        
        // Run the users function - we save some code because gfxThreadExit() never returns
        //      gfxThreadExit(_gfxCurrentThread->fn(_gfxCurrentThread->param));
        ldr      r2,=__cpp(&_gfxCurrentThread)
        ldr      r2,[r2,#0]
        ldr      r0,[r2,#__cpp(offsetof(thread,param))]
        ldr      r1,[r2,#__cpp(offsetof(thread,fn))]
        blx      r1
        mov      r4,r0
        bl       __cpp(gfxThreadExit)
        
        ALIGN
    }
 
#else
    #if GFX_COMPILER_WARNING_TYPE == GFX_COMPILER_WARNING_DIRECT
        #warning "GOS Threads: You have specified a specific CPU but your compiler is not supported. Defaulting to CLIB switching"
    #elif GFX_COMPILER_WARNING_TYPE == GFX_COMPILER_WARNING_MACRO
        COMPILER_WARNING("GOS Threads: You have specified a specific CPU but your compiler is not supported. Defaulting to CLIB switching")
    #endif
#endif