/* * Copyright (c) 2007, Takahide Matsutsuka. * All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above * copyright notice, this list of conditions and the following * disclaimer in the documentation and/or other materials provided * with the distribution. * 3. The name of the author may not be used to endorse or promote * products derived from this software without specific prior * written permission. * * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS * OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE * GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. * */ /* * \file * Z80 machine-specific implementation for supporting multithread. * \author * Takahide Matsutsuka <markn@markn.org> */ #include "sys/mt.h" #include "mtarch.h" /*--------------------------------------------------------------------------*/ void mtarch_init(void) { } /*--------------------------------------------------------------------------*/ void mtarch_start(struct mtarch_thread *t, void (*function)(void *), void *data) { u16_t i; for(i = 0; i < MTARCH_STACKSIZE; i++) { t->stack[i] = i; } t->sp = &t->stack[MTARCH_STACKSIZE - 1]; /* A parameter for method for thread function. */ *t->sp = (u16_t)data; --t->sp; /* This will be a return address of thread function. */ *t->sp = (u16_t)mt_exit; --t->sp; /* The thread function, is used as a return address of mtarch_switch. */ *t->sp = (u16_t)function; --t->sp; /* * Space for registers. * af, bc, de, hl, ix, iy, af', bc', de', hl' */ /* * Z80 stack basis: * push stores the data AFTER decrementing sp. * pop reads the data BEFORE incrementing sp. */ t->sp = t->sp - 9; } /*--------------------------------------------------------------------------*/ static struct mtarch_thread *running_thread; static u16_t *sptmp; static void mtarch_switch() { __asm di ; disable interrupt ; normal registers push af push bc push de push hl push ix push iy ; back registers ex af,af' push af exx push bc push de push hl ; swap between running_thread->sp and SP reg ; _running_thread in asembler below points running_thread->sp ; sptmp = sp; ld (_sptmp),sp ; sp = *(running_thread->sp); ld ix,(_running_thread) ld l,0(ix) ld h,1(ix) ld sp,hl ; running_thread->sp = sptmp; ld hl,(_sptmp) ld 0(ix),l ld 1(ix),h ; back registers pop hl pop de pop bc exx pop af ex af,af' ; normal registers pop iy pop ix pop hl pop de pop bc pop af ei ; enable interrupt __endasm; // here sp indicates the address that point the function } /*--------------------------------------------------------------------------*/ void mtarch_exec(struct mtarch_thread *t) { running_thread = t; mtarch_switch(); running_thread = NULL; } /*--------------------------------------------------------------------------*/ void mtarch_remove() { } /*--------------------------------------------------------------------------*/ void mtarch_yield() { if (running_thread == NULL) { /* ERROR! we have no runnning thread. */ return; } mtarch_switch(); } /*--------------------------------------------------------------------------*/ void mtarch_stop(struct mtarch_thread *thread) { } /*--------------------------------------------------------------------------*/ void mtarch_pstop() { } /*--------------------------------------------------------------------------*/ void mtarch_pstart() { } /*--------------------------------------------------------------------------*/ int mtarch_stack_usage(struct mtarch_thread *t) { u16_t i; for (i = 0; i < MTARCH_STACKSIZE; i++) { if (t->stack[i] != i) { return MTARCH_STACKSIZE - i; } } return 0; } /*--------------------------------------------------------------------------*/