Zilog Z8F0130 - Manual (Page 230)

Using the ANSI C-Compiler UM013037-1212
206
Zilog Developer Studio II – Z8 Encore!
User Manual
The asm statement cannot be within an expression and can be used only within the body of
a function.
The <assembly line> can be any string.The compiler does not check the legality of the
string.
As with the #pragma asm form, the compiler does not process the <assembly line>
except for translating the standard C escape sequences.
The compiler prefixes the name of every global variable with an underscore (_). Global
variables can therefore be accessed in inline assembly by prefixing their name with “_”.
The local variables and parameters cannot be accessed in inline assembly.
Placement Directives
The Zilog C-Compiler provides language extensions for the following directives:
•
Placement of a Variable – see page 206
•
Placement of Consecutive Variables – see page 206
•
Alignment of a Variable – see page 207
Placement of a Variable
The following syntax can be used to declare a global or static variable at an address:
char placed_char _At 0xff; // placed_char is assigned an address
0xff.

far struct {

char ch;

int ii;

} ss _At 0xeff; // ss is assigned an address 0xeff


rom char init_char _At 0xffff = 33;

// init_char is in rom and initialized to 33
Only placed variables with rom storage class specifier can be initialized. The placed vari-
ables with near and far storage class specifier cannot be initialized. The uninitialized
placed variables are not initialized to zero by the compiler start-up routine.
Placement of Consecutive Variables
The compiler also provides syntax to place several variables at consecutive addresses.
For example:
Note: