Data definition or allocation directives

In this section:

Syntax

DC8 expr [,expr] ...

DC16 expr [,expr] ...

DC24 expr [,expr] ...

DC32 expr [,expr] ...

DC64 expr [,expr] ...

DF32 value [,value] ...

DF64 value [,value] ...

DQ15 value [,value] ...

DQ31 value [,value] ...

DS. [size] count

DS count

DS8 count

DS16 count

DS24 count

DS32 count

DS64 count

Parameters

`count`	A valid absolute expression specifying the number of elements to be reserved.
`expr`	A valid absolute, relocatable, or external expression, or an ASCII string. ASCII strings are zero filled to a multiple of the data size implied by the directive. Double-quoted strings are zero-terminated. For `DC64`, `expr` cannot be relocatable or external.
`value`	A valid absolute expression or floating-point constant.

Description

These directives define values or reserve memory.

Use DC8, DC16, DC24, DC32, DC64, DF32, or DF64 to create a constant, which means an area of bytes is reserved big enough for the constant.

Use DS, DS8, DS16, DS24, DS32, or DS64 to reserve a number of uninitialized bytes.

For information about the restrictions that apply when using a directive in an expression, see Expression restrictions.

The column Alias in the following table shows the Renesas directive that corresponds to the IAR directive.

Directive	Alias	Description
`DC8`		Generates 8-bit constants, including strings.
`DC16`		Generates 16-bit constants.
`DC24`		Generates 24-bit constants.
`DC32`		Generates 32-bit constants.
`DC64`		Generates 64-bit constants.
`DF32`		Generates 32-bit floating-point constants.
`DF64`		Generates 64-bit floating-point constants.
`DQ15`		Generates 16-bit fractional constants.
`DQ31`		Generates 32-bit fractional constants.
`DS8`	`DS`	Allocates space for 8-bit integers.
`DS16`		Allocates space for 16-bit integers.
`DS24`		Allocates space for 24-bit integers.
`DS32`		Allocates space for 32-bit integers.
`DS64`		Allocates space for 64-bit integers.

Table 130. Data definition or allocation directives

Generating a lookup table

This example generates a constant table of 8-bit data that is accessed via the call instruction and added up to a sum.

            module  sumTableAndIndex
            section .text:CONST(2)

table:      dc8     12
            dc8     15
            dc8     17
            dc8     16
            dc8     14
            dc8     13
            dc8     11
            dc8     9

            section .text:CODE(2)
count:      set     0

addTable:   mov     table,r6
            rept    7
            if      count == 7
            exitm
            endif
            ld.b    count[r6],r10
            set     count + 1
            add     1,r10
            st.b    r10,count[r6]
            endr
            jmp     [lp]
            end

Defining strings

To define a string:

myMsg   DC8 'Please enter your name'

To define a string which includes a trailing zero:

myCstr  DC8 "This is a string."

To include a single quote in a string, enter it twice, for example:

errMsg  DC8 'Don''t understand!'

Reserving space

To reserve space for 10 bytes:

table   DS8   10

IAR Embedded Workbench for RH850 3.20.x