User manual

Project creation and build UM0036
102/385 Doc ID 7705 Rev 11
Minimum number of bytes for activation of factorization
This field allows you to enter an integer for the number of bytes required to trigger the
factorization feature. Entering an integer adds the -of option to the command line with the
integer specifying the number of bytes that triggers factorization. Any value less than 4
disables the factorization. The default value for triggering factorization is 7.
This option is not available with the ST7 C compiler versions under 4.4.
Generate jump table checkbox (for ST7 only)
When checked, this options creates a jump table using the -l option to generate a listing
file, then linking the full application to generate the jmptab.s file. This is a necessary step
prior to using the Optimize Function Calls (+jmp) option. Be careful not to disable -l via the
interface for the listing settings (see Customizing Cosmic C compiler listings on page 104).
Optimize function calls (for ST7only)
After compiling your application to generate a jump table, this option enables the
optimization of function calls to reduce the volume of code. However, it also creates a time
overhead at each function call.
When checked, this introduces the +jmp option on the command line. You cannot check
this option if you have not already compiled the application to generate a jump table.
Customizing Cosmic C compiler language settings
To further customize optimizations, select Customize from the list box. Alternatively, from
the Category list box, select C language. The view in the C Compiler tab changes to that
shown in Figure 67.
Display removed/modified
instruction statistics (-ov)
Write a log of modifications to STDERR. This displays the
number of removed instructions followed by the number of
modified instructions.
No Constant Propagation (-pcp)
Introduces the -pcp option on the command line, which
disables the constant propagation optimization. By default,
when a variable is assigned with a constant, any subsequent
access to that variable is replaced by the constant itself until
the variable is modified or a flow break is encountered.
This option is not available with the ST7 C compiler versions
under 4.4.
1. For complete descriptions of compiler optimizations, refer to the C Cross Compiler User’s Guide.
Table 34. Cosmic C compiler optimization options (continued)
Option
(1)
Description