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<A NAME="CHILD_LINKS"><STRONG>Subsections</STRONG></A>
<UL>
<LI><A NAME="tex2html2086"
HREF="node94.html#SECTION004172100000000000000">3.17.2.1 <stdio.h></A>
<UL>
<LI><A NAME="tex2html2087"
HREF="node94.html#SECTION004172110000000000000">3.17.2.1.1 getchar(), putchar()</A>
<LI><A NAME="tex2html2088"
HREF="node94.html#SECTION004172120000000000000">3.17.2.1.2 printf()</A>
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<LI><A NAME="tex2html2089"
HREF="node94.html#SECTION004172200000000000000">3.17.2.2 <malloc.h></A>
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<H2><A NAME="SECTION004172000000000000000">
3.17.2 Stdclib functions (puts, printf, strcat etc.)</A>
</H2>
<P>
<H3><A NAME="SECTION004172100000000000000">
3.17.2.1 <stdio.h></A>
</H3>
<P>
<H4><A NAME="SECTION004172110000000000000">
3.17.2.1.1 getchar(), putchar()</A>
</H4>
<P>
<A NAME="2484"></A>As usual on embedded systems you have to provide
your own <TT>getchar()<A NAME="2485"></A></TT> and <TT>putchar()<A NAME="2486"></A><A NAME="2487"></A></TT>
routines. SDCC does not know whether the system connects to a serial
line with or without handshake, LCD, keyboard or other device. And
whether a <TT>lf</TT> to <TT>crlf</TT> conversion within <TT>putchar()</TT>
is intended. You'll find examples for serial routines f.e. in sdcc/device/lib.
For the mcs51 this minimalistic polling <TT>putchar()</TT> routine
might be a start:
<BLOCKQUOTE>
<TT>void putchar (char c) { </TT>
<BR><TT> while (!TI) /* assumes UART is initialized
*/</TT>
<BR><TT> ;</TT>
<BR><TT> TI = 0;</TT>
<BR><TT> SBUF = c;</TT>
<BR><TT>}</TT>
</BLOCKQUOTE>
<P>
<H4><A NAME="SECTION004172120000000000000">
3.17.2.1.2 printf()</A>
</H4>
<P>
The default <TT>printf()<A NAME="2502"></A></TT> implementation in <TT>printf_large.c</TT>
does not support float<A NAME="2504"></A> (except on ds390),
only <NO FLOAT><A NAME="2505"></A><A NAME="2506"></A>
will be printed instead of the value. To enable floating point output,
recompile it with the option <I>-DUSE_FLOATS=1<A NAME="2507"></A></I>
on the command line. Use <I>--model-large<A NAME="2508"></A></I>
for the mcs51 port, since this uses a lot of memory. To enable float
support for the pic16 targets, see <A HREF="node128.html#sub:pic16Libraries">4.6.9</A>.
<P>
If you're short on code memory you might want to use <TT>printf_small()<A NAME="2510"></A></TT>
<I>instead</I> of <TT>printf().</TT> For the mcs51 there additionally
are assembly versions <TT>printf_tiny()<A NAME="2513"></A></TT>
(subset of printf using less than 270 bytes) and <TT>printf_fast()<A NAME="2514"></A></TT>
and <TT>printf_fast_f()<A NAME="2515"></A></TT>
(floating-point aware version of printf_fast) which should fit the
requirements of many embedded systems (printf_fast() can be customized
by unsetting #defines to <I>not</I> support long variables and field
widths). Be sure to use only one of these printf options within a
project.
<BR>
<P>
Feature matrix of different <I>printf</I> options on mcs51.
<P>
<TABLE CELLPADDING=3 BORDER="1">
<TR><TH ALIGN="LEFT" VALIGN="MIDDLE" WIDTH=0>
<B><FONT SIZE="+1">mcs51</FONT></B> </TH>
<TD ALIGN="CENTER">printf<A NAME="2528"></A></TD>
<TD ALIGN="LEFT" VALIGN="TOP" WIDTH=0>
<DIV ALIGN="CENTER">
printf <FONT SIZE="-2">USE_FLOATS=1</FONT>
</DIV></TD>
<TD ALIGN="LEFT" VALIGN="TOP" WIDTH=0>
<DIV ALIGN="CENTER">
printf_small
</DIV></TD>
<TD ALIGN="CENTER">printf_fast</TD>
<TD ALIGN="LEFT" VALIGN="TOP" WIDTH=0>
<DIV ALIGN="CENTER">
printf_fast_f
</DIV></TD>
<TD ALIGN="CENTER">printf_tiny</TD>
</TR>
<TR><TD ALIGN="LEFT" VALIGN="MIDDLE" WIDTH=0>
filename </TD>
<TD ALIGN="CENTER"><FONT SIZE="-2">printf_large.c</FONT></TD>
<TD ALIGN="LEFT" VALIGN="TOP" WIDTH=0>
<DIV ALIGN="CENTER">
<FONT SIZE="-2">printf_large.c</FONT>
</DIV></TD>
<TD ALIGN="LEFT" VALIGN="TOP" WIDTH=0>
<DIV ALIGN="CENTER">
<FONT SIZE="-2">printfl.c</FONT>
</DIV></TD>
<TD ALIGN="CENTER"><FONT SIZE="-2">printf_fast.c</FONT></TD>
<TD ALIGN="LEFT" VALIGN="TOP" WIDTH=0>
<DIV ALIGN="CENTER">
<FONT SIZE="-2">printf_fast_f.c</FONT>
</DIV></TD>
<TD ALIGN="CENTER"><FONT SIZE="-2">printf_tiny.c</FONT></TD>
</TR>
<TR><TD ALIGN="LEFT" VALIGN="MIDDLE" WIDTH=0>
''Hello World'' size
<P>
small / large </TD>
<TD ALIGN="CENTER">1.7k / 2.4k</TD>
<TD ALIGN="LEFT" VALIGN="TOP" WIDTH=0>
<DIV ALIGN="CENTER">
4.3k / 5.6k
</DIV></TD>
<TD ALIGN="LEFT" VALIGN="TOP" WIDTH=0>
<DIV ALIGN="CENTER">
1.2k / 1.8k
</DIV></TD>
<TD ALIGN="CENTER">1.3k / 1.3k</TD>
<TD ALIGN="LEFT" VALIGN="TOP" WIDTH=0>
<DIV ALIGN="CENTER">
1.9k / 1.9k
</DIV></TD>
<TD ALIGN="CENTER">0.44k / 0.44k</TD>
</TR>
<TR><TD ALIGN="LEFT" VALIGN="MIDDLE" WIDTH=0>
code size
<P>
small / large </TD>
<TD ALIGN="CENTER">1.4k / 2.0k</TD>
<TD ALIGN="LEFT" VALIGN="TOP" WIDTH=0>
<DIV ALIGN="CENTER">
2.8k / 3.7k
</DIV></TD>
<TD ALIGN="LEFT" VALIGN="TOP" WIDTH=0>
<DIV ALIGN="CENTER">
0.45k / 0.47k (+ _ltoa)
</DIV></TD>
<TD ALIGN="CENTER">1.2k / 1.2k</TD>
<TD ALIGN="LEFT" VALIGN="TOP" WIDTH=0>
<DIV ALIGN="CENTER">
1.6k / 1.6k
</DIV></TD>
<TD ALIGN="CENTER">0.26k / 0.26k</TD>
</TR>
<TR><TD ALIGN="LEFT" VALIGN="MIDDLE" WIDTH=0>
formats </TD>
<TD ALIGN="CENTER">cdi<I>o</I>psux</TD>
<TD ALIGN="LEFT" VALIGN="TOP" WIDTH=0>
<DIV ALIGN="CENTER">
cdfi<I>o</I>psux
</DIV></TD>
<TD ALIGN="LEFT" VALIGN="TOP" WIDTH=0>
<DIV ALIGN="CENTER">
cd<I>o</I>sx
</DIV></TD>
<TD ALIGN="CENTER">cdsux</TD>
<TD ALIGN="LEFT" VALIGN="TOP" WIDTH=0>
<DIV ALIGN="CENTER">
cdfsux
</DIV></TD>
<TD ALIGN="CENTER">cdsux</TD>
</TR>
<TR><TD ALIGN="LEFT" VALIGN="MIDDLE" WIDTH=0>
long (32 bit) support </TD>
<TD ALIGN="CENTER">x</TD>
<TD ALIGN="LEFT" VALIGN="TOP" WIDTH=0>
<DIV ALIGN="CENTER">
x
</DIV></TD>
<TD ALIGN="LEFT" VALIGN="TOP" WIDTH=0>
<DIV ALIGN="CENTER">
x
</DIV></TD>
<TD ALIGN="CENTER">x</TD>
<TD ALIGN="LEFT" VALIGN="TOP" WIDTH=0>
<DIV ALIGN="CENTER">
x
</DIV></TD>
<TD ALIGN="CENTER">-</TD>
</TR>
<TR><TD ALIGN="LEFT" VALIGN="MIDDLE" WIDTH=0>
byte arguments on stack </TD>
<TD ALIGN="CENTER">b</TD>
<TD ALIGN="LEFT" VALIGN="TOP" WIDTH=0>
<DIV ALIGN="CENTER">
b
</DIV></TD>
<TD ALIGN="LEFT" VALIGN="TOP" WIDTH=0>
<DIV ALIGN="CENTER">
-
</DIV></TD>
<TD ALIGN="CENTER">-</TD>
<TD ALIGN="LEFT" VALIGN="TOP" WIDTH=0>
<DIV ALIGN="CENTER">
-
</DIV></TD>
<TD ALIGN="CENTER">-</TD>
</TR>
<TR><TD ALIGN="LEFT" VALIGN="MIDDLE" WIDTH=0>
float format<A NAME="2539"></A> </TD>
<TD ALIGN="CENTER">-</TD>
<TD ALIGN="LEFT" VALIGN="TOP" WIDTH=0>
<DIV ALIGN="CENTER">
%f
</DIV></TD>
<TD ALIGN="LEFT" VALIGN="TOP" WIDTH=0>
<DIV ALIGN="CENTER">
-
</DIV></TD>
<TD ALIGN="CENTER">-</TD>
<TD ALIGN="LEFT" VALIGN="TOP" WIDTH=0>
<DIV ALIGN="CENTER">
%f<A NAME="tex2html42"
HREF="footnode.html#foot2540"><SUP>3.10</SUP></A>
</DIV></TD>
<TD ALIGN="CENTER">-</TD>
</TR>
<TR><TD ALIGN="LEFT" VALIGN="MIDDLE" WIDTH=0>
float formats %e %g </TD>
<TD ALIGN="CENTER">-</TD>
<TD ALIGN="LEFT" VALIGN="TOP" WIDTH=0>
<DIV ALIGN="CENTER">
-
</DIV></TD>
<TD ALIGN="LEFT" VALIGN="TOP" WIDTH=0>
<DIV ALIGN="CENTER">
-
</DIV></TD>
<TD ALIGN="CENTER">-</TD>
<TD ALIGN="LEFT" VALIGN="TOP" WIDTH=0>
<DIV ALIGN="CENTER">
-
</DIV></TD>
<TD ALIGN="CENTER">-</TD>
</TR>
<TR><TD ALIGN="LEFT" VALIGN="MIDDLE" WIDTH=0>
field width </TD>
<TD ALIGN="CENTER">x</TD>
<TD ALIGN="LEFT" VALIGN="TOP" WIDTH=0>
<DIV ALIGN="CENTER">
x
</DIV></TD>
<TD ALIGN="LEFT" VALIGN="TOP" WIDTH=0>
<DIV ALIGN="CENTER">
-
</DIV></TD>
<TD ALIGN="CENTER">x</TD>
<TD ALIGN="LEFT" VALIGN="TOP" WIDTH=0>
<DIV ALIGN="CENTER">
x
</DIV></TD>
<TD ALIGN="CENTER">-</TD>
</TR>
<TR><TD ALIGN="LEFT" VALIGN="MIDDLE" WIDTH=0>
string speed<A NAME="tex2html43"
HREF="footnode.html#foot5906"><SUP>3.11</SUP></A>,
<P>
small / large </TD>
<TD ALIGN="CENTER">1.52 / 2.59 ms</TD>
<TD ALIGN="LEFT" VALIGN="TOP" WIDTH=0>
<DIV ALIGN="CENTER">
1.53 / 2.62 ms
</DIV></TD>
<TD ALIGN="LEFT" VALIGN="TOP" WIDTH=0>
<DIV ALIGN="CENTER">
0.92 / 0.93 ms
</DIV></TD>
<TD ALIGN="CENTER">0.45 / 0.45 ms</TD>
<TD ALIGN="LEFT" VALIGN="TOP" WIDTH=0>
<DIV ALIGN="CENTER">
0.46 / 0.46 ms
</DIV></TD>
<TD ALIGN="CENTER">0.45 / 0.45 ms</TD>
</TR>
<TR><TD ALIGN="LEFT" VALIGN="MIDDLE" WIDTH=0>
int speed<A NAME="tex2html44"
HREF="footnode.html#foot5907"><SUP>3.12</SUP></A>,
<P>
small / large </TD>
<TD ALIGN="CENTER">3.01 / 3.61 ms</TD>
<TD ALIGN="LEFT" VALIGN="TOP" WIDTH=0>
<DIV ALIGN="CENTER">
3.01 / 3.61 ms
</DIV></TD>
<TD ALIGN="LEFT" VALIGN="TOP" WIDTH=0>
<DIV ALIGN="CENTER">
3.51 / 18.13 ms
</DIV></TD>
<TD ALIGN="CENTER">0.22 / 0.22 ms</TD>
<TD ALIGN="LEFT" VALIGN="TOP" WIDTH=0>
<DIV ALIGN="CENTER">
0.23 / 0.23 ms
</DIV></TD>
<TD ALIGN="CENTER">0.25 / 0.25 ms<A NAME="tex2html45"
HREF="footnode.html#foot2551"><SUP>3.13</SUP></A></TD>
</TR>
<TR><TD ALIGN="LEFT" VALIGN="MIDDLE" WIDTH=0>
long speed<A NAME="tex2html46"
HREF="footnode.html#foot5908"><SUP>3.14</SUP></A>,
<P>
small / large </TD>
<TD ALIGN="CENTER">5.37 / 6.31 ms</TD>
<TD ALIGN="LEFT" VALIGN="TOP" WIDTH=0>
<DIV ALIGN="CENTER">
5.37 / 6.31 ms
</DIV></TD>
<TD ALIGN="LEFT" VALIGN="TOP" WIDTH=0>
<DIV ALIGN="CENTER">
8.71 / 40.65 ms
</DIV></TD>
<TD ALIGN="CENTER">0.40 / 0.40 ms</TD>
<TD ALIGN="LEFT" VALIGN="TOP" WIDTH=0>
<DIV ALIGN="CENTER">
0.40 / 0.40 ms
</DIV></TD>
<TD ALIGN="CENTER">-</TD>
</TR>
<TR><TD ALIGN="LEFT" VALIGN="MIDDLE" WIDTH=0>
float speed<A NAME="tex2html47"
HREF="footnode.html#foot5909"><SUP>3.15</SUP></A>,
<P>
small / large </TD>
<TD ALIGN="CENTER">-</TD>
<TD ALIGN="LEFT" VALIGN="TOP" WIDTH=0>
<DIV ALIGN="CENTER">
7.49 / 22.47 ms
</DIV></TD>
<TD ALIGN="LEFT" VALIGN="TOP" WIDTH=0>
<DIV ALIGN="CENTER">
-
</DIV></TD>
<TD ALIGN="CENTER">-</TD>
<TD ALIGN="LEFT" VALIGN="TOP" WIDTH=0>
<DIV ALIGN="CENTER">
1.04 / 1.04 ms
</DIV></TD>
<TD ALIGN="CENTER">-</TD>
</TR>
</TABLE>
<P>
<H3><A NAME="SECTION004172200000000000000"></A><A NAME="2557"></A>
<BR>
3.17.2.2 <malloc.h>
</H3>
<P>
As of SDCC 2.6.2 you no longer need to call an initialization routine
before using dynamic memory allocation<A NAME="2558"></A>
and a default heap<A NAME="2559"></A> space of 1024 bytes is provided
for malloc to allocate memory from. If you need a different heap size
you need to recompile _heap.c with the required size defined in HEAP_SIZE.
It is recommended to make a copy of this file into your project directory
and compile it there with:
<BLOCKQUOTE>
<TT>sdcc -c _heap.c -D HEAP_SIZE=2048</TT>
</BLOCKQUOTE>
And then link it with:
<BLOCKQUOTE>
<TT>sdcc main.rel _heap.rel</TT>
</BLOCKQUOTE>
<P>
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