printf.c

一款MP3 Player Firmware 的原代码,非常有参考价值

/* Fast printf routine for use with sdcc/mcs51
 * Copyright (c) 2001, Paul Stoffregen, [e-mail]
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version 2
 * of the License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
 */


#define LONG_INT
#define FIELD_WIDTH


// extern void putchar(char );


// #define COUT 0x0030
// #define PHEX 0x0034
// #define PHEX16 0x0036
// #define NEWLINE 0x003A


#define COUT 0x2030
#define PHEX 0x2034
#define PHEX16 0x2036
#define NEWLINE 0x203A


static bit long_flag, short_flag, print_zero_flag, negative_flag;

#ifdef FIELD_WIDTH
static bit field_width_flag;
static bit leading_zero_flag;
static data unsigned char field_width;
#endif

bit at 0x1F debug;





void printfd(code char *fmt, ...) reentrant
{
        fmt;    /* suppress unreferenced variable warning */

        if (debug == 0) return;
        _asm ljmp printf_begin _endasm;
}


void printf(code char *fmt, ...) reentrant
{
	fmt;	/* supress unreferenced variable warning */

	_asm

printf_begin:
	mov	a, _bp		// r0 will point to va_args (stack)
	add	a, #253
	mov	r0, a		// r0 points to MSB of fmt
	mov	dph, @r0
	dec	r0
	mov	dpl, @r0	// dptr has address of fmt
	dec	r0

printf_main_loop:
	clr	a
	movc	a, @a+dptr	// get next byte of fmt string
	inc	dptr
	//cjne	a, #'%', printf_normal
	cjne	a, #37, printf_normal

printf_format:
	clr	_long_flag
	clr	_short_flag
	clr	_print_zero_flag
	clr	_negative_flag
#ifdef FIELD_WIDTH
	clr	_field_width_flag
	clr	_leading_zero_flag
	mov	_field_width, #0
#endif

printf_format_loop:
	clr	a
	movc	a, @a+dptr	// get next byte of data format
	inc	dptr

	/* parse and consume the field width digits, even if */
	/* we don't build the code to make use of them */
	add	a, #198
	jc	printf_nondigit1
	add	a, #10
	jnc	printf_nondigit2
#ifdef FIELD_WIDTH
printf_digit:
	jnz	printf_digit_2
	cjne	a, _field_width, printf_digit_2
	setb	_leading_zero_flag
printf_digit_2:
	setb	_field_width_flag
	mov	r1, a
	mov	a, _field_width
	mov	b, #10
	mul	ab
	add	a, r1
	mov	_field_width, a
#endif
	sjmp	printf_format_loop
printf_nondigit1:
	add	a, #10
printf_nondigit2:
	add	a, #48


printf_format_l:
	//cjne	a, #'l', printf_format_h
	cjne	a, #108, printf_format_h
	setb	_long_flag
	sjmp	printf_format_loop

printf_format_h:
	//cjne	a, #'h', printf_format_s
	cjne	a, #104, printf_format_s
	setb	_short_flag
	sjmp	printf_format_loop

printf_format_s:
	//cjne	a, #'s', printf_format_d
	cjne	a, #115, printf_format_d
	ljmp	printf_string

printf_format_d:
	//cjne	a, #'d', printf_format_u
	cjne	a, #100, printf_format_u
	lcall	printf_get_int
	ljmp	printf_int

printf_format_u:
	//cjne	a, #'u', printf_format_c
	cjne	a, #117, printf_format_c
	lcall	printf_get_int
	ljmp	printf_uint

printf_format_c:
	//cjne	a, #'c', printf_format_x
	cjne	a, #99, printf_format_x
	mov	a, @r0		// Acc has the character to print
	dec	r0
	sjmp	printf_char

printf_format_x:
	//cjne	a, #'x', printf_normal
	cjne	a, #120, printf_normal
	ljmp	printf_hex

printf_normal:
	jz	printf_eot
printf_char:
	lcall	printf_putchar
	sjmp	printf_main_loop

printf_eot:
	ljmp	printf_end




	/* print a string... just grab each byte with __gptrget */
	/* the user much pass a 24 bit _generic pointer */

printf_string:
	push	dph		// save addr in fmt onto stack
	push	dpl
	mov	b, @r0		// b has type of address (_generic *)
	dec	r0
	mov	dph, @r0
	dec	r0
	mov	dpl, @r0	// dptr has address of user's string
	dec	r0

#ifdef FIELD_WIDTH
	jnb	_field_width_flag, printf_str_loop
	clr	_leading_zero_flag	// never leading zeros for strings
	push	dpl
	push	dph
printf_str_fw_loop:
	lcall	__gptrget
	jz	printf_str_space
	inc	dptr
	dec	_field_width
	mov	a, _field_width
	jnz	printf_str_fw_loop
printf_str_space:
	lcall	printf_space
	pop	dph
	pop	dpl
#endif // FIELD_WIDTH

printf_str_loop:
	lcall	__gptrget
	jz	printf_str_done
	inc	dptr
	lcall	printf_putchar
	sjmp	printf_str_loop
printf_str_done:
	pop	dpl		// restore addr withing fmt
	pop	dph
	ljmp	printf_main_loop








	/* printing in hex is easy because sdcc pushes the LSB first */

printf_hex:
	lcall	printf_hex8
	jb	_short_flag, printf_hex_end
	lcall	printf_hex8
	jnb	_long_flag, printf_hex_end
	lcall	printf_hex8
	lcall	printf_hex8
printf_hex_end:
	lcall	printf_zero
	ljmp	printf_main_loop
printf_hex8:
	mov	a, @r0
	lcall	printf_phex_msn
	mov	a, @r0
	dec	r0
	ljmp	printf_phex_lsn


#ifndef LONG_INT
printf_ld_in_hex:
	//mov	a, #'0'
	mov	a, #48
	lcall	printf_putchar
	//mov	a, #'x'
	mov	a, #120
	lcall	printf_putchar
	mov	a, r0
	add	a, #4
	mov	r0, a
	sjmp	printf_hex
#endif


	/* printing an integer is not so easy.  For a signed int */
	/* check if it is negative and print the minus sign and */
	/* invert it to a positive integer */

printf_int:
	mov	a, r5
	jnb	acc.7, printf_uint	/* check if negative */
	setb	_negative_flag
	mov	a, r1			/* invert integer */
	cpl	a
	addc	a, #1
	mov	r1, a
	jb	_short_flag, printf_uint
	mov	a, r2
	cpl	a
	addc	a, #0
	mov	r2, a
	jnb	_long_flag, printf_uint
	mov	a, r3
	cpl	a
	addc	a, #0
	mov	r3, a
	mov	a, r4
	cpl	a
	addc	a, #0
	mov	r4, a


	/* printing integers is a lot of work... because it takes so */
	/* long, the first thing to do is make sure we're doing as */
	/* little work as possible, then convert the binary int to */
	/* packed BCD, and finally print each digit of the BCD number */

printf_uint:

	jb	_short_flag, printf_uint_ck8
	jnb	_long_flag, printf_uint_ck16
printf_uint_ck32:
	/* it's a 32 bit int... but if the upper 16 bits are zero */
	/* we can treat it like a 16 bit integer and convert much faster */
#ifdef LONG_INT
	mov	a, r3
	jnz	printf_uint_begin
	mov	a, r4
	jnz	printf_uint_begin
#else
	mov	a, r3
	jnz	printf_ld_in_hex	;print long integer as hex
	mov	a, r4			;rather than just the low 16 bits
	jnz	printf_ld_in_hex
#endif
	clr	_long_flag
printf_uint_ck16:
	/* it's a 16 bit int... but if the upper 8 bits are zero */
	/* we can treat it like a 8 bit integer and convert much faster */
	mov	a, r2
	jnz	printf_uint_begin
	setb	_short_flag
printf_uint_ck8:
	/* it's an 8 bit int... if it's zero, it's a lot faster to just */
	/* print the digit zero and skip all the hard work! */
	mov	a, r1
	jnz	printf_uint_begin
#ifdef FIELD_WIDTH
	jnb	_field_width_flag, printf_uint_zero
	dec	_field_width
	lcall	printf_space
#endif
printf_uint_zero:
	//mov	a, #'0'
	mov	a, #48
	lcall	printf_putchar
	ljmp	printf_main_loop


printf_uint_begin:
	push	dpl
	push	dph
	lcall	printf_int2bcd		// bcd number in r3/r2/r7/r6/r5

#ifdef FIELD_WIDTH
	jnb	_field_width_flag, printf_uifw_end
#ifdef LONG_INT
printf_uifw_32:
	mov	r1, #10
	jnb	_long_flag, printf_uifw_16
	mov	a, r3
	anl	a, #0xF0
	jnz	printf_uifw_sub
	dec	r1
	mov	a, r3
	anl	a, #0x0F
	jnz	printf_uifw_sub
	dec	r1
	mov	a, r2
	anl	a, #0xF0
	jnz	printf_uifw_sub
	dec	r1
	mov	a, r2
	anl	a, #0x0F
	jnz	printf_uifw_sub
	dec	r1
	mov	a, r7
	anl	a, #0xF0
	jnz	printf_uifw_sub
#endif
printf_uifw_16:
	mov	r1, #5
	jb	_short_flag, printf_uifw_8
	mov	a, r7
	anl	a, #0x0F
	jnz	printf_uifw_sub
	dec	r1
	mov	a, r6
	anl	a, #0xF0
	jnz	printf_uifw_sub
printf_uifw_8:
	mov	r1, #3
	mov	a, r6
	anl	a, #0x0F
	jnz	printf_uifw_sub
	dec	r1
	mov	a, r5
	anl	a, #0xF0
	jnz	printf_uifw_sub
	dec	r1
printf_uifw_sub:
	;r1 has the number of digits for the number
	mov	a, _field_width
	mov	c, _negative_flag
	subb	a, r1
	jc	printf_uifw_end
	mov	_field_width, a

#ifdef LONG_INT
	push	ar3
	push	ar2
#endif
	push	ar7
	push	ar6
	push	ar5
	lcall	printf_space
	pop	ar5
	pop	ar6
	pop	ar7
#ifdef LONG_INT
	pop	ar2
	pop	ar3
#endif
printf_uifw_end:
#endif


printf_uint_doit:
	jnb	_negative_flag, printf_uint_pos
	//mov	a, #"-"
	mov	a, #45
	lcall	printf_putchar
printf_uint_pos:
	jb	_short_flag, printf_uint8
#ifdef LONG_INT
	jnb	_long_flag, printf_uint16
printf_uint32:
	push	ar5
	push	ar6
	push	ar7
	mov	dpl, r2
	mov	a, r3
	mov	dph, a
	lcall	printf_phex_msn
	mov	a, dph
	lcall	printf_phex_lsn
	mov	a, dpl
	lcall	printf_phex_msn
	mov	a, dpl
	lcall	printf_phex_lsn
	pop	acc
	mov	dpl, a
	lcall	printf_phex_msn
	mov	a, dpl
	pop	dph
	pop	dpl
	sjmp	printf_uint16a
#endif

printf_uint16:
	mov	dpl, r5
	mov	dph, r6
	mov	a, r7
printf_uint16a:
	lcall	printf_phex_lsn
	mov	a, dph
	lcall	printf_phex_msn
	mov	a, dph
	sjmp	printf_uint8a

printf_uint8:
	mov	dpl, r5
	mov	a, r6
printf_uint8a:
	lcall	printf_phex_lsn
	mov	a, dpl
	lcall	printf_phex_msn
	mov	a, dpl
	lcall	printf_phex_lsn
	lcall	printf_zero
	pop	dph
	pop	dpl
	ljmp	printf_main_loop











	/* read an integer into r1/r2/r3/r4, and msb into r5 */
printf_get_int:
	mov	a, @r0
	mov	r1, a
	mov	r5, a
	dec	r0
	jb	_short_flag, printf_get_done
	mov	r2, ar1
	mov	a, @r0
	mov	r1, a
	dec	r0
	jnb	_long_flag, printf_get_done