The
TMS34010
C
Language
'
4.8
Initialization
of
Static
and
Global
Variables
K&RB.6
An important difference between K&R C and TMS3401 0 C
is
that external and
static variables
are
not pre-initialized
to
zero unless the program explicitly does
so
or
it
is specified
as
an
option in the linker, GSPLNK.
If
a program requires that external and static variables be pre-initialized, the
linker
can
be
used to do this. In the linker control file,
use
a fill value
of
0 in
the
.bss section:
SECTIONS
.bssO
= bxOO;
}
4.9
8sm
Statement
Addi-
tional
4·8
TMS34010
C
has
another "statement"
not
mentioned in K&R: the asm state-
ment. This statement allows assembly
language text
to
be imbedded in the
output
assembler source file. The form
of
the asm statement
is:
asm("<assembler
text)");
The assembler text is enclosed in double quotes. All the usual character string
escape codes have their normal meaning.
The assembler text
is
copied directly
to the assembler source file. Note that for GSPA,'
an
assembler text statement
without
a label must begin
with
a blank. '
The
asm statement injects one line
of
assembly language into the
output
of
the codegen. A series
of
asm commands places the instructions sequentially
into the codegen output
with
no intervening code.
Asm
statements do
not
follow
the syntactic restrictions
of
normal statements
and
can
appear anywhere in the C source, even outside blocks. However, they
are
ignored when they appear in a list
of
declarations.
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