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4.2.6.1 Allocation of function and data to section

The CC-RH controls allocation to memory or the access method by allocating functions or data to sections.

-	Sections for functions

Table 4.11

Types of Sections for Functions

Section Relocation Attribute	Default Section Name	Access Method	Alignment Condition
text	.text	32-bit relative mode from r0	2
pctext	.pctext	32-bit relative mode from PC	2

-	The .text section is used by default.

This section cannot be used by the PIC facility.

-	The .pctext section is a section to be used by the PIC facility.

-	R0-relative sections for data

Table 4.12

Types of R0-Relative Sections for Data

Section Relocation Attribute	Default Section Name	Data to be Allocated	Access Method	Alignment Condition
zdata	.zdata	Variables with initial value	16-bit relative mode from r0	4
zbss	.zbss	Variables with no initial value	16-bit relative mode from r0
zdata23	.zdata23	Variables with initial value	23-bit relative mode from r0
zbss23	.zbss23	Variables with no initial value	23-bit relative mode from r0
data	.data	Variables with initial value	32-bit relative mode from r0
bss	.bss	Variables with no initial value	32-bit relative mode from r0

-	The .data and .bss sections are used by default.

-	The .zdata, .zbss, .zdata23, and .zbss23 sections are used for access in a short instruction length.

-	Any of the R0-relative sections cannot be used by the PID facility.

-	EP-relative sections for data

Table 4.13

Types of EP-Relative Sections for Data

Section Relocation Attribute	Default Section Name	Data to be Allocated	Access Method	Alignment Condition
tdata4	.tdata4	Variables with initial value	4-bit relative mode from r30 (EP) The sld or sst instruction can be used.	4
tbss4	.tbss4	Variables with no initial value
tdata5	.tdata5	Variables with initial value	5-bit relative mode from r30 (EP) The sld or sst instruction can be used.
tbss5	.tbss5	Variables with no initial value
tdata7	.tdata7	Variables with initial value	7-bit relative mode from r30 (EP) The sld or sst instruction can be used.
tbss7	.tbss7	Variables with no initial value
tdata8	.tdata8	Variables with initial value	8-bit relative mode from r30 (EP) The sld or sst instruction can be used.
tbss8	.tbss8	Variables with no initial value
edata	.edata	Variables with initial value	16-bit relative mode from r30 (EP)
ebss	.ebss	Variables with no initial value	16-bit relative mode from r30 (EP)
edata23	.edata23	Variables with initial value	23-bit relative mode from r30 (EP)
ebss23	.ebss23	Variables with no initial value	23-bit relative mode from r30 (EP)
edata32	.edata32	Variables with initial value	32-bit relative mode from r30 (EP)
ebss32	.ebss32	Variables with no initial value	32-bit relative mode from r30 (EP)

-	The .tdata* and .tbss* sections are used for access in a short instruction length.

The sld or sst instruction which is even shorter can be used.

These sections can be used even by the PID facility.

-	The .edata, .ebss, .edata23, and .ebss23 sections are used for access in a short instruction length.

These sections can be used even by the PID facility.

-	The .edata32 and .ebss32 sections are sections to be used by the PID facility.

-	GP-relative sections for data

Table 4.14

Types of GP-Relative Sections for Data

Section Relocation Attribute	Default Section Name	Data to be Allocated	Access Method	Alignment Condition
sdata	.sdata	Variables with initial value	16-bit relative mode from r4 (GP)	4
sbss	.sbss	Variables with no initial value	16-bit relative mode from r4 (GP)
sdata23	.sdata23	Variables with initial value	23-bit relative mode from r4 (GP)
sbss23	.sbss23	Variables with no initial value	23-bit relative mode from r4 (GP)
sdata32	.sdata32	Variables with initial value	32-bit relative mode from r4 (GP)
sbss32	.sbss32	Variables with no initial value	32-bit relative mode from r4 (GP)

-	The .sdata, .sbss, .sdata23, and .sbss23 sections are used for access in a short instruction length.

These sections can be used even by the PID facility.

-	The .sdata32 and .sbss32 sections are sections to be used by the PID facility.

-	Sections for constant data

Table 4.15

Types of Sections for Constant Data

Section Relocation Attribute	Default Section Name	Data to be Allocated	Access Method	Alignment Condition
zconst	.zconst	const variables String literal Initial values of auto variablesNote 1	16-bit relative mode from r0	4
zconst23	.zconst23		23-bit relative mode from r0
const	.const		32-bit relative mode from r0
pcconst16	.pcconst16		16-bit relative mode from the __pc_data symbol
pcconst23	.pcconst23		23-bit relative mode from the __pc_data symbol
pcconst32	.pcconst32		32-bit relative mode from the __pc_data symbol

Note 1.

The initial values of auto variables are in the .const section when the PIROD facility is not used and are in the .pcconst32 section when the PIROD facility is used. In either case, they cannot be changed.

-	The .const section is used by default.

This section cannot be used by the PIROD facility.

-	The .zconst and .zconst23 sections are used for access in a short instruction length.

These sections cannot be used by the PIROD facility.

-	The .pcconst16, .pcconst23, and .pconst32 sections are sections to be used by the PIROD facility.

The sections to which the CC-RH allocates functions or data are the four sections .text, .data, .bss, and .const, by default.

The longer the relative distance at access is, the access is in a long instruction length and the code size is increased.

The CC-RH can allocate functions and data to desired sections using the extended facilities. This makes it possible to generate code using the relocation attribute characteristics of each section.

(1)	#pragma section directive

Describe the #pragma section directive in the following format.

#pragma section data attribute-strings-for-data "user-defined-name" [V2.03.00 or later]

or

#pragma section data attribute-strings-for-data [V2.03.00 or later]

-	The allocation section of data is changed. The functions and constant data are not affected.

#pragma section const attribute-strings-for-constant-data "user-defined-name" [V2.03.00 or later]

or

#pragma section const attribute-strings-for-constant-data [V2.03.00 or later]

-	The allocation section of constant data is changed. The functions and constant data are not affected.

-	To change the allocation section of functions, describe as:

#pragma section attribute-strings "user-defined-name"

or

#pragma section attribute-strings

-	The allocation sections of functions, data or constant data are changed.

-	When specifying the attribute strings for data, the allocation section of constant data is changed to the default section (.const).

-	When specifying the attribute strings for constant data, the allocation section of data is changed to the default section (.data or .bss).

#pragma section user-defined-name

-	The relocation attributes of functions, data and constant data are changed to their defaults, and the sections names are changed according to the user defined names.

#pragma section text default [V2.03.00 or later]

-	The allocation section of functions is changed to the default section (.text). The data and constant data are not affected.

#pragma section data default [V2.03.00 or later]

-	The allocation section of data is changed to the default section (.data or .bss). The functions and constant data are not affected.

#pragma section const default [V2.03.00 or later]

-	The allocation section of constant data is changed to the default section (.const). The functions and data are not affected.

#pragma section default

or

#pragma section

-	The allocation sections of functions, data and constant data are changed to the default sections (.text, .data, .bss, .const).

Section relocation attributes are specified using "attribute strings", and section names are specified using "user-defined names". The usable attribute strings vary depending on the specified options.

The relationship between specifiable attribute strings, corresponding section relocation attributes, and options that can be specified as conditions is shown in Table 4.16, Table 4.17, and Table 4.18.

Attribute strings are case-sensitive.

Table 4.16

Relationship between Attribute Strings for Functions and Section Relocation Attributes

Attribute String	Section Relocation Attribute	Specifiable Condition
text	text	When -pic is not specified
pctext [V1.07.00 or later]	pctext	When -pic is specified

Table 4.17

Relationship between Attribute Strings for Data and Section Relocation Attributes

Attribute String	Section Relocation Attribute	Specifiable Condition
r0_disp16	zdata/zbss	When -pid is not specified
r0_disp23	zdata23/zbss23
r0_disp32	data/bss
ep_disp4	tdata4/tbss4	When -Xep=fix is specified
ep_disp5	tdata5/tbss5
ep_disp7	tdata7/tbss7
ep_disp8	tdata8/tbss8
ep_disp16	edata/ebss
ep_disp23	edata23/ebss23
ep_disp32 [V1.07.00 or later]	edata32/ebss32	When -Xep=fix and -pid are both specified
gp_disp16	sdata/sbss	When -r4=fix is specified
gp_disp23	sdata23/sbss23	When -r4=fix is specified
gp_disp32 [V1.07.00 or later]	sdata32/sbss32	When -r4=fix and -pid are both specified

Table 4.18

Relationship between Attribute Strings for Constant Data and Section Relocation Attributes

Attribute String	Section Relocation Attribute	Specifiable Condition
zconst	zconst	When -pirod is not specified
zconst23	zconst23
const	const
pcconst16 [V1.07.00 or later]	pcconst16	When -pirod is specified
pcconst23 [V1.07.00 or later]	pcconst23
pcconst32 [V1.07.00 or later]	pcconst32

The following characters are usable in user-defined names.

0 to 9

-	a to z, A to Z

The allocation section of functions or data written after a #pragma section directive is determined in accordance with the following rules.

1. The relocation attribute is determined from the "attribute string".

(1) For data, *data* or *bss* is automatically selected depending on whether there is an initial value.

(2) A format with no attribute string has an effect on both functions and data, and the default relocation attribute of the compiler is used.

2. A string representing the relocation attribute is linked after the "user-defined name"Note.

(1) If the user-defined name starts with a number from 0 to 9, "_" is added to the beginning.

(2) If there is no user-defined name, the default section name is used without change.

Note	This is to prevent sections with different section relocation attributes from having the same section name.

3. When the format of #pragma section default or #pragma section is specified, it has an effect on both functions and data, and the default relocation attribute of the compiler and the default section name are used.

A #pragma section directive is valid from the position where it was written up to the position where the next #pragma section directive appears or up to the end of the source file.

Example

#pragma section gp_disp16 "foo"

int a = 1;        /* foo.sdata */

int b;            /* foo.sbss */

#pragma section zconst23 "bar"

const int c = 2;  /* bar.zconst23 */

#pragma section text "123"

void func() {}    /* _123.text */

#pragma section baz

int d = 3;        /* baz.data */

int e;            /* baz.bss */

const int f = 4;  /* baz.const */

void func2() {}   /* baz.text */

#pragma section default

int g = 3;        /* .data */

int h;            /* .bss */

const int i = 4;  /* .const */

void func3() {}   /* .text */

The effect of a #pragma section directive differs between variables and functions.

Variable

If there are multiple declarations and definitions for a variable and a different #pragma section directive is specified for each, the #pragma section directive that appears first is valid.

Example

int x = 1;    /* Variable x is allocated to foo.data */

int y = 2;    /* Variable y is allocated to bar.data */

#pragma section foo

extern int x;

#pragma section bar

extern int x;

extern int y;

Function

When the -pic option is not specified, #pragma section is valid only for function definitions.

When the -pic option is specified, similar as to variables, #pragma section is valid for both declarations and definitions.

[V2.02.00 or later] #pragma section can also be described within a function.

Therefore, #pragma section within a function is now valid, which was ignored and caused W0520609 to be output in V2.01.00 or earlier.

Due to this specification change, if there are multiple static variables within the function or multiple string literals, each value can be allocated to separate sections.

Example

void func() {

  #pragma section AAA

  static int aaa;         /* AAA.bss */

  #pragma section BBB

  static int bbb;         /* BBB.bss */

  #pragma section

static int ccc;           /* .bss */