分类:
2012-10-28 13:52:44
The DATA_SECTION pragma allocates space for the symbol in a section called section name.
The syntax for the pragma in C is:
#pragma DATA_SECTION (symbol, "section name");
The syntax for the pragma in C++ is:
#pragma DATA_SECTION ( "section name");
The DATA_SECTION pragma is useful if you have data objects that you want to link into an area separate from the .bss section.
This directive is illustrated in the following example.
Using the DATA_SECTION Pragma
a) C source file
#pragma DATA_SECTION(bufferB, "my_sect")
char bufferA[512];
char bufferB[512]:
// 执行完此三条语句之后,数组bufferB被分配到段名为 "my_sect"的自定义段中
b) C++ source file
char bufferA[512];
#pragma DATA_SECTION("my_sect")
char bufferB[512];
c) Assembly source file
.global _bufferA
.bss _bufferA,512,4
.global _bufferB
_bufferB: .usect "my_sect",512,4
///////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
The CODE_SECTION pragma allocates space for the func in a section named section name. The CODE_SECTION pragma is useful if you have code objects that you want to link into an area separate from the .text section.
The syntax of the pragma in C is:
#pragma CODE_SECTION (func, section name)
The syntax of the pragma in C++ is:
#pragma CODE_SECTION (section name)
The following example demonstrates the use of the CODE_SECTION pragma.
Using the CODE_SECTION Pragma
a) C source file
char bufferA[80];
char bufferB[80];
#pragma CODE_SECTION(funcA, codeA)
char funcA(int i);
char funcB(int i);
void main()
{
char c;
c = funcA(1);
c = funcB(2);
}
char funcA (int i)
{
return bufferA;
}
char funcB (int j)
{
return bufferB[j];
}
b) Assembly source file
.sect ".text" .global _main;***************************************************************
;* FNAME: _main FR SIZE: 2 *
;* *
;* FUNCTION ENVIRONMENT *
;* *
;* FUNCTION PROPERTIES *
;* 0 Parameter, 1 Auto, 0 SOE *
;***************************************************************
_main:
ADDB SP,#2
MOVB AL,#1 ; |12|
LCR #_funcA ; |12|
; call occurs [#_funcA] ; |12|
MOV *-SP[1],AL ; |12|
MOVB AL,#1 ; |13|
LCR #_funcB ; |13|
; call occurs [#_funcB] ; |13|
MOV *-SP[1],AL ; |13|
SUBB SP,#2
LRETR
; return occurs
.sect "codeA"
.global _funcA
;***************************************************************
;* FNAME: _funcA FR SIZE: 1 *
;* *
;* FUNCTION ENVIRONMENT *
;* *
;* FUNCTION PROPERTIES *
;* 0 Parameter, 1 Auto, 0 SOE *
;***************************************************************
_funcA:
ADDB SP,#1
MOV *-SP[1],AL ; |17|
MOVZ AR6,*-SP[1] ; |18|
ADD AR6,#_bufferA ; |18|
SUBB SP,#1 ; |18|
MOV AL,*+XAR6[0] ; |18|
LRETR
;return occurs
.sect ".text"
.global _funcB
;***************************************************************
;* FNAME: _funcB FR SIZE: 1 *
;* *
;* FUNCTION ENVIRONMENT *
;* *
;* FUNCTION PROPERTIES *
;* 0 Parameter, 1 Auto, 0 SOE *
;***************************************************************
_funcB:
ADDB SP,#1
MOV *-SP[1],AL ; |22|
MOVZ AR6,*-SP[1] ; |23|
ADD AR6,#_bufferB ; |23|
SUBB SP,#1 ; |23|
MOV AL,*+XAR6[0] ; |23|
LRETR
;return occurs
// 从红色标记可以看出,在加入#pragma CODE_SECTION(funcA, codeA)语句之后,main()函数和_funcB函数被
// 分配到 ".text" 段中,而_funcA函数被分配到 "codeA" 段中。