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/* Copyright (c) 2005,2007 Dmitry Xmelkov
All rights reserved.
Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions are met:
* Redistributions of source code must retain the above copyright
notice, this list of conditions and the following disclaimer.
* 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.
* Neither the name of the copyright holders nor the names of
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. */
/* $Id: ultoa_invert.S,v 1.1.2.1 2008/03/16 13:44:44 dmix Exp $ */
#ifndef __DOXYGEN__
#include "macros.inc"
#include "ntz.h"
#include "xtoa_fast.h"
/* --------------------------------------------------------------------
char * __ultoa_invert (unsigned long val, char * str, int base)
This function is intended for usage as internal printf's one.
It differs from others of `xtoa_fast' family:
* srt[] will NOT 0 terminated.
* Sequence of digits is inverted.
* It returns pointer to first byte after a string.
* Only `XTOA_UPPER' flag is operated.
Notes:
* base: check only 8 and 16, all others are treated as 10.
(internal printf's function).
*/
/* Input */
#define v_lo r22
#define v_hi r23
#define v_hlo r24
#define v_hhi r25
#define str_lo r20
#define str_hi r21
#define base r18
#define flags r19
/* Used */
#define v_fifth r26 /* val: bits 39..32 */
#define t_lo r18 /* temporary for shifted `val' */
#define t_hi r19
#define t_hlo r20
#define t_hhi r21
#define symb r20 /* write to string */
#define cnt r27 /* shift loop counter, local arg */
/* Fixed */
#define rzero r1
.text
.global __ultoa_invert
.type __ultoa_invert, "function"
__ultoa_invert:
X_movw ZL, str_lo
clr v_fifth ; needed for all (ultoa_lsr)
cpi base, 8
breq .L_oct
cpi base, 16
breq .L_hex
; decimal format
clt ; flag of val == 0
.L_dec_loop:
push v_lo ; to calculate remander
; val &= ~1
andi v_lo, ~1
; val += 2
subi v_lo, lo8(-2)
sbci v_hi, hi8(-2)
sbci v_hlo, hlo8(-2)
sbci v_hhi, hhi8(-2)
sbci v_fifth, hhi8(-2)
; val += val/2
ldi cnt, 1
rcall .L_div_add
; val += val/16
ldi cnt, 4
rcall .L_div_add
; val += val/256
add v_lo, v_hi
adc v_hi, v_hlo
adc v_hlo, v_hhi
adc v_hhi, v_fifth
adc v_fifth, rzero
; val += val/65536
add v_lo, v_hlo
adc v_hi, v_hhi
adc v_hlo, v_fifth
adc v_hhi, rzero
adc v_fifth, rzero
; val += val >> 32
add v_lo, v_fifth
adc v_hi, rzero
adc v_hlo, rzero
adc v_hhi, rzero
adc v_fifth, rzero
; division result: val /= 16
rcall .L_lsr_4 ; v_fitth := 0
brne 1f
set ; T := Z flag
1:
; rem: val_original - 10*val
pop t_hi
#if defined(__AVR_ENHANCED__) && __AVR_ENHANCED__
ldi t_lo, 10
mul t_lo, v_lo
clr r1
#else
mov r0, v_lo
lsl r0
sub t_hi, r0
lsl r0
lsl r0
#endif
sub t_hi, r0
; output digit
subi t_hi, lo8(-'0')
st Z+, t_hi
; quotient == 0 ?
brtc .L_dec_loop
; end of string
.L_eos:
X_movw r24, ZL
ret
; octal format
.L_oct:
mov symb, v_lo
andi symb, 7
subi symb, lo8(-'0')
st Z+, symb
ldi cnt, 3
rcall .L_lsr
brne .L_oct
rjmp .L_eos
; hex format
.L_hex:
mov symb, v_lo
andi symb, 0x0f
subi symb, lo8(-'0')
cpi symb, '9' + 1
brlo 3f
subi symb, lo8('9' + 1 - 'a')
sbrc flags, ntz(XTOA_UPPER) - 8
subi symb, lo8('a' - 'A')
3: st Z+, symb
rcall .L_lsr_4
brne .L_hex
rjmp .L_eos
.L_lsr_4:
ldi cnt, 4
.L_lsr:
lsr v_fifth
ror v_hhi
ror v_hlo
ror v_hi
ror v_lo
dec cnt
brne .L_lsr
; tst
sbiw v_hlo, 0 ; only Z flag is needed
cpc v_lo, rzero
cpc v_hi, rzero
ret
.L_div_add:
; copy to temporary
X_movw t_lo, v_lo
X_movw t_hlo, v_hlo
mov r0, v_fifth
; lsr temporary
7: lsr r0
ror t_hhi
ror t_hlo
ror t_hi
ror t_lo
dec cnt
brne 7b
; add
add v_lo, t_lo
adc v_hi, t_hi
adc v_hlo, t_hlo
adc v_hhi, t_hhi
adc v_fifth, r0 ; here r0 == 0
ret
.size __ultoa_invert, . - __ultoa_invert
.end
#endif /* !__DOXYGEN__ */
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