Epson S5U1C17001C Manual page 371

Function: Generate code for 20-bit (1MB) space
Description: This option is used to generate codes in which the data space and branch address range are limited to
20-bit (1MB space).
When this option is specified, the C compiler uses only one ext instruction for extending the
immediate data in the data access/branch instructions to reduce code size. This limits the range of
data accessing and conditional branching to a 1MB space. However, the call and jpr branch
instructions are not limited to 1MB, as one ext instruction extends them to branch within a 24-bit
range. This option is useful to reduce code size for applications of which the program and data can be
located in a 1MB space. The C compiler always output 's' extended instructions (sld, sjreq, etc.),
not 'x' extended instructions (xld, xjreq, etc.).
Default: The C compiler generates objects that allow data/program to be located in the 24-bit (16MB)
space.
Option
-mpointer16
-mshort-offset
*1 Use the ANSI C and emulation libraries for 24-bit memory model (located in \lib\24bit).
*2 Use the ANSI C and emulation libraries for 16-bit memory model (located in \lib\16bit).
*3 Use the -mpointer16 option in conjunction with the -mshort-offset option.
-Wall
Function: Enables warning options.
Description: This function enables all of the following warning options.
These warning options can be individually disabled by adding "-Wno-." For example, to disable
just the "-Wcomment" warning, add "-Wno-comment" after "-Wall."
-Wchar-subscripts
Outputs a warning when the subscript of an array is of the type "char."
-Wcomment
Outputs a warning when "/*" the starting character string for a comment line occurs inside a
comment beginning with "/*." Also outputs a warning when a comment starting with "//" ends
with a backslash.
-Wformat
Checks whether the argument is appropriate for a converted character string when the printf or
scanf function is invoked. Also checks whether the conversion specified by the converted character
string is appropriate.
-Wimplicit-int
Outputs a warning if a format is not specified when a variable or function is declared.
-Wimplicit-function-declaration
Outputs a warning when a function is used before declaration.
-Wimplicit
Same as "-Wimplicit-int" and "-Wimplicit-function-declaration" in enabled
state.
-Wmain
Outputs a warning when the format of the main function is incorrect. The main function has an
external linkage and the return value is in int format. It should have 0, 2, or 3 arguments of the
appropriate format.
-Wmissing-braces
Outputs a warning when parentheses are used incorrectly during initialization of arrays. For
S5U1C17001C ManUal
(C COMPilEr PaCkagE fOr S1C17 faMily) (Ver. 1.5.0)
Table 6.3.2.1 -mpointer16 and -mshort-offset option settings
Data/Program space
*1
24 bits (16MB)
Code is generated with a 24-
bit data pointer
Use entire space
Do not specify (default)
Do not specify (default)
EPSOn
*1
20 bits (1MB) 16 bits (64kB)
Code is generated with a 24-
bit data pointer
reduce code size reduce code and raM size
Do not specify (default)
Specify
6 C COMPilEr
*2
Code is generated with a 16-
bit data pointer
*3
Specify
*3
Specify
6-5
6
Compiler