nuttx/arch/avr/src/atmega/atmega_head.S

/****************************************************************************
 * arch/avr/src/atmega/atmega_head.S
 *
 *   Copyright (C) 2011 Gregory Nutt. All rights reserved.
 *   Author: Gregory Nutt <gnutt@nuttx.org>
 *
 * 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. Neither the name NuttX nor the names of its contributors may be
 *	used to endorse or promote products derived from this software
 *	without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "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
 * COPYRIGHT OWNER OR CONTRIBUTORS 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.
 *
 ****************************************************************************/

/****************************************************************************
 * Included Files
 ****************************************************************************/

#include <nuttx/config.h>

#include <arch/irq.h>
#include <avr/io.h>
#include <avr/sfr_defs.h>

/****************************************************************************
 * Pre-processor definitions
 ****************************************************************************/

/* Stack is allocated just after uninitialized data and just before the heap */

#define STACKBASE (_enoinit+CONFIG_IDLETHREAD_STACKSIZE-1)

/* The RAMPZ register is only available for CPUs with more than 64Kb of FLASH.
 * At present, only the ATMega128 is supported so RAMPZ should always be
 * available.
 *
 * - Support for the EPLMX instructions is assumed if RAMPZ is present
 * - If RAMPZ is not present, support for LPMX is assumed
 */

#define HAVE_RAMPZ 1

/****************************************************************************
 * External Symbols
 ****************************************************************************/

	.file	"up_nommuhead.S"
	.global	__start			/* Entry point */
	.global	_sbss			/* Start of .bss.  Defined by ld.script */
	.global	_ebss			/* End of .bss.  Defined by ld.script */
	.global	_sdata			/* Start of .data section in RAM */
	.global	_edata			/* End of .data section in RAM */
	.global	_eronly			/* Start of .data section in FLASH */
	.global	_enoinit		/* End of uninitilized data.  Defined by ld.script */
	.global	up_lowinit		/* Perform low level initialization */
	.global	os_start		/* NuttX entry point */

	.global	vectortab
	.global	atmega_int0		/* External interrupt request 0 */
	.global	atmega_int1		/* External interrupt request 1 */
	.global	atmega_int2		/* External interrupt request 2 */
	.global	atmega_int3		/* External interrupt request 3 */
	.global	atmega_int4		/* External interrupt request 4 */
	.global	atmega_int5		/* External interrupt request 5 */
	.global	atmega_int6		/* External interrupt request 6 */
	.global	atmega_int7		/* External interrupt request 7 */
	.global	atmega_t2comp	/* TIMER2 COMP timer/counter2 compare match */
	.global	atmega_t2ovf	/* TIMER2 OVF timer/counter2 overflow */
	.global	atmega_t1capt	/* TIMER1 CAPT timer/counter1 capture event */
	.global	atmega_t1compa	/* TIMER1 COMPA timer/counter1 compare match a */
	.global	atmega_t1compb	/* TIMER1 COMPB timer/counter1 compare match b */
	.global	atmega_t1ovf	/* TIMER1 OVF timer/counter1 overflow */
	.global	atmega_t0comp	/* TIMER0 COMP timer/counter0 compare match */
	.global	atmega_t0ovf	/* TIMER0 OVF timer/counter0 overflow */
	.global	atmega_spi		/* STC SPI serial transfer complete */
	.global	atmega_u0rx		/* USART0 RX complete */
	.global	atmega_u0dre	/* USART0 data register empty */
	.global	atmega_u0tx		/* USART0 TX complete */
	.global	atmega_adc		/* ADC conversion complete */
	.global	atmega_ee		/* EEPROM ready */
	.global	atmega_anacomp	/* ANALOG COMP analog comparator */
	.global	atmega_t1compc	/* TIMER1 COMPC timer/countre1 compare match c */
	.global	atmega_t3capt	/* TIMER3 CAPT timer/counter3 capture event */
	.global	atmega_t3compa	/* TIMER3 COMPA timer/counter3 compare match a */
	.global	atmega_t3compb	/* TIMER3 COMPB timer/counter3 compare match b */
	.global	atmega_t3compc	/* TIMER3 COMPC timer/counter3 compare match c */
	.global	atmega_t3ovf	/* TIMER3 OVF timer/counter3 overflow */
	.global	atmega_u1rx		/* USART1 RX complete */
	.global	atmega_u1dre	/* USART1 data register empty */
	.global	atmega_u1tx		/* USART1 TX complete */
	.global	atmega_twi		/* TWI two-wire serial interface */
	.global	atmega_spmrdy	/* Store program memory ready */

/****************************************************************************
 * Macros
 ****************************************************************************/

	.macro	vector name
	jmp		\name
	.endm

/****************************************************************************
 * Vector Table
 ****************************************************************************/

/* The ATmega128 has 35 interrupt vectors including vector 0, the reset
 * vector.
 */

	.section .vectors, "ax", @progbits
	.func	vectortab
vectortab:
	jmp		__start			/*  0: Vector 0 is the reset vector */
	vector	atmega_int0		/*  1: External interrupt request 0 */
	vector	atmega_int1		/*  2: External interrupt request 1 */
	vector	atmega_int2		/*  3: External interrupt request 2 */
	vector	atmega_int3		/*  4: External interrupt request 3 */
	vector	atmega_int4		/*  5: External interrupt request 4 */
	vector	atmega_int5		/*  6 : External interrupt request 5 */
	vector	atmega_int6		/*  7: External interrupt request 6 */
	vector	atmega_int7		/*  8: External interrupt request 7 */
	vector	atmega_t2comp	/*  9: TIMER2 COMP timer/counter2 compare match */
	vector	atmega_t2ovf	/* 10: TIMER2 OVF timer/counter2 overflow */
	vector	atmega_t1capt	/* 11: TIMER1 CAPT timer/counter1 capture event */
	vector	atmega_t1compa	/* 12: TIMER1 COMPA timer/counter1 compare match a */
	vector	atmega_t1compb	/* 13: TIMER1 COMPB timer/counter1 compare match b */
	vector	atmega_t1ovf	/* 14: TIMER1 OVF timer/counter1 overflow */
	vector	atmega_t0comp	/* 15: TIMER0 COMP timer/counter0 compare match */
	vector	atmega_t0ovf	/* 16: TIMER0 OVF timer/counter0 overflow */
	vector	atmega_spi		/* 17: STC SPI serial transfer complete */
	vector	atmega_u0rx		/* 18: USART0 RX complete */
	vector	atmega_u0dre	/* 19: USART0 data register empty */
	vector	atmega_u0tx		/* 20: USART0 TX complete */
	vector	atmega_adc		/* 21: ADC conversion complete */
	vector	atmega_ee		/* 22: EEPROM ready */
	vector	atmega_anacomp	/* 23: ANALOG COMP analog comparator */
	vector	atmega_t1compc	/* 24: TIMER1 COMPC timer/countre1 compare match c */
	vector	atmega_t3capt	/* 25: TIMER3 CAPT timer/counter3 capture event */
	vector	atmega_t3compa	/* 26: TIMER3 COMPA timer/counter3 compare match a */
	vector	atmega_t3compb	/* 27: TIMER3 COMPB timer/counter3 compare match b */
	vector	atmega_t3compc	/* 28: TIMER3 COMPC timer/counter3 compare match c */
	vector	atmega_t3ovf	/* 29: TIMER3 OVF timer/counter3 overflow */
	vector	atmega_u1rx		/* 30: USART1 RX complete */
	vector	atmega_u1dre	/* 31: USART1 data register empty */
	vector	atmega_u1tx		/* 32: USART1 TX complete */
	vector	atmega_twi		/* 33: TWI two-wire serial interface */
	vector	atmega_spmrdy	/* 34: Store program memory ready */
	.endfunc

/****************************************************************************
 * Reset Entry Point
 ****************************************************************************/

	.section .init, "ax", @progbits
	.func	__start
__start:

	/* Clear the zero register, clear the status register and initialize the
	 * IDLE thread stack
	 */

	clr		r1
	out		_SFR_IO_ADDR(SREG), r1
	ldi		r28, lo8(STACKBASE)
	ldi		r29, hi8(STACKBASE)
	out		_SFR_IO_ADDR(SPH), r29
	out		_SFR_IO_ADDR(SPL), r28

	/* Copy initial global data values from FLASH into RAM */

    .global __do_copy_data;     /* Required to suppress dragging in logic from libgcc */
__do_copy_data:

#ifdef HAVE_RAMPZ
	ldi		r17, hi8(_edata)
	ldi		r26, lo8(_sdata)
	ldi		r27, hi8(_sdata)
	ldi		r30, lo8(_eronly)
	ldi		r31, hi8(_eronly)
	ldi		r16, hh8(_eronly)
	out		_SFR_IO_ADDR(RAMPZ), r16
	rjmp	.Lcopystart

.Lcopyloop:
	elpm	r0, Z+
	st		X+, r0

.Lcopystart:
	cpi		r26, lo8(_edata)
	cpc		r27, r17
	brne	.Lcopyloop
#else
	ldi		r17, hi8(_edata)
	ldi		r26, lo8(_sdata)
	ldi		r27, hi8(_sdata)
	ldi		r30, lo8(_eronly)
	ldi		r31, hi8(_eronly)
	rjmp	.Lcopystart

.Lcopyloop:
	lpm     r0, Z+
	st      X+, r0

.Lcopystart:
	cpi     r26, lo8(_edata)
	cpc     r27, r17
	brne    .Lcopyloop
#endif

	/* Clear uninitialized data */

    .global __do_clear_bss;     /* Required to suppress dragging in logic from libgcc */
__do_clear_bss:

	ldi		r17, hi8(_ebss)
	ldi		r26, lo8(_sbss)
	ldi		r27, hi8(_sbss)
	rjmp	.Lclearstart

.Lclearloop:
	st		X+, r1
 
.Lclearstart:
	cpi		r26, lo8(_ebss)
	cpc		r27, r17
	brne	.Lclearloop

	/* Perform any low-level initialization */

	call	up_lowinit

	/* Now start NuttX */

	call	os_start
	jmp		exit
	.endfunc

/****************************************************************************
 * Heap Base
 ****************************************************************************/

	/* This global variable is unsigned long g_idle_topstack and is exported from
	 * here only because of its coupling to other uses of _enoinit in this file
	 */

	.data
	.globl	g_idle_topstack
	.type	g_idle_topstack, object
g_idle_topstack:
	.word	_enoinit+CONFIG_IDLETHREAD_STACKSIZE
	.size	g_idle_topstack, .-g_idle_topstack
	.end