retarget.c

以ARM9为CPU的嵌入式系统的USB驱动程序

/*
 * Copyright (C) ARM Limited, 1999. All rights reserved.
 */


/*
This implements a 'retarget' layer for low-level IO.  Typically, this would
contain your own target-dependent implementations of fputc(), ferror(), etc.
This example provides implementations of fputc(), ferror(), _sys_exit(),
_ttywrch() and __user_initial_stackheap().
Here, semihosting SWIs are used to display text onto the console of the host debugger.
This mechanism is portable across ARMulator, Angel, Multi-ICE and EmbeddedICE.
Alternatively, to output characters from the serial port of an ARM Development (PID) Board
(see serial.c), use '#define USE_SERIAL_PORT' or compile with '-DUSE_SERIAL_PORT'.
*/
#include "AT91RM9200.h"
#include "lib_AT91RM9200.h"

#include <stdio.h>
#include <rt_misc.h>

#define USE_SERIAL_PORT

#ifdef __thumb
/* Thumb Semihosting SWI */
#define SemiSWI 0xAB
#else
/* ARM Semihosting SWI */
#define SemiSWI 0x123456
#endif


/* Write a character */
__swi(SemiSWI) void _WriteC(unsigned op, char *c);
#define WriteC(c) _WriteC (0x3,c)

/* Exit */
__swi(SemiSWI) void _Exit(unsigned op, unsigned except);
#define Exit() _Exit (0x18,0x20026)


struct __FILE {
	char misc;
};

struct __FILE __stdout;
struct __FILE __stdin;


int fputc(int ch, FILE *f)
{
    /* Place your implementation of fputc here */
    /* e.g. write a character to a UART, or to the debugger console with SWI WriteC */

	while (!AT91F_US_TxReady((AT91PS_USART)AT91C_BASE_DBGU));
	AT91F_US_PutChar((AT91PS_USART)AT91C_BASE_DBGU, ch);

    if (ch == '\n') {
		while (!AT91F_US_TxReady((AT91PS_USART)AT91C_BASE_DBGU));
		AT91F_US_PutChar((AT91PS_USART)AT91C_BASE_DBGU, '\r');
	}
    return ch;
}


int ferror(FILE *f)
{   /* Your implementation of ferror */
    return EOF;
}

int fgetc(FILE *f)
{
	if (AT91F_US_RxReady((AT91PS_USART)AT91C_BASE_DBGU))
		return AT91F_US_GetChar((AT91PS_USART)AT91C_BASE_DBGU);
	else
		return EOF;
}

void _sys_exit(int return_code)
{
    Exit();         /* for debugging */

label:  goto label; /* endless loop */
}


void _ttywrch(int ch)
{
#ifdef USE_SERIAL_PORT
	fputc(ch, stdout);
#else
    char tempch = ch;
    WriteC( &tempch );
#endif
}


//__value_in_regs struct __initial_stackheap __user_initial_stackheap(
struct __initial_stackheap __user_initial_stackheap(
        unsigned r0, unsigned sp, unsigned r2, unsigned sl)
{
    struct __initial_stackheap config;

    return config;
}

/*
To place heap_base directly above the ZI area, use e.g:
    extern unsigned int Image$$ZI$$Limit;
    config.heap_base = (unsigned int)&Image$$ZI$$Limit;
(or &Image$$region_name$$ZI$$Limit for scatterloaded images)

To specify the limits for the heap & stack, use e.g:
    config.heap_limit = SL;
    config.stack_limit = SL;
*/