Specifications

CAVR-4
Part 2. Compiler reference
Compiler options
173
Descriptions of options
The following section gives detailed reference information about each compiler option.
--char_is_signed --char_is_signed
By default, the compiler interprets the char type as unsigned. The --char_is_signed
option causes the compiler to interpret the char type as signed instead. This can be
useful when you, for example, want to maintain compatibility with another compiler.
Note: The runtime library is compiled without the
--char_is_signed option. If you
use this option, you may get type mismatch warnings from the IAR XLINK Linker,
because the library uses unsigned chars.
To set the equivalent option in IAR Embedded Workbench, select
Project>Options>C/C++ Compiler>Language.
--cpu --cpu=cpu
Use this option to select the processor for which the code is to be generated.
For example, use the following command to specify the AT90S4414 derivative:
--cpu=4414
See Processor configuration, page 5, for a summary of the available processor variants.
Note that to specify the processor, you can use either the
--cpu option or the -v option.
The
--cpu option is, however, more precise because it contains more information about
the intended target than the more generic -v option. For information about the implicit
assumptions using the -v option, see -v, page 197.
This option is related to the Processor configuration option in the General Options
category in IAR Embedded Workbench.
--zero_register Specifies register R15 as
zero register
--64bit_doubles Use 64-bit doubles
--64k_flash Specifies a maximum of 64
Kbytes flash memory.
Command line option Description
Table 43: Compiler options summary (Continued)