Zilog Z8F0130 - Manual (Page 240)

Using the ANSI C-Compiler UM013037-1212
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Zilog Developer Studio II – Z8 Encore!
User Manual
7. Return.

All registers, other than the return register, are considered as caller save; that is, they are
saved and restored by the caller function. The flag register is not saved and restored by the
caller function.
The function call mechanism described in this section is a dynamic call mechanism. In a
dynamic call mechanism, each function allocates memory on the stack for its locals and
temporaries during the run time of the program. When the function has returned, the

memory that it was using is freed from the stack. Figure 138 shows a diagram of the Z8
Encore! C-Compiler dynamic call frame layout.
For functions that are declared to be monitor functions by the use of #pragma _monitor ,
the saved value of the interrupt control register (IRQCTL) will be inserted on the stack
between the caller’s frame pointer and the return address.
Function Call Mechanism: Static Frame
A function (caller function) performs the following tasks when it calls another function
which has a static call frame (called function):
Figure 138. Dynamic Call Frame Layout
Temporaries
Locals
Callers Frame Pointer
Small Model: 8:0
Large Model: 16:0
Return Address 16:0
Parameter 0
Parameter 1
…
Parameter N
FP
SP
Run Time Stack
High Address
Low Address
Note: