MSC100ABIRM Motorola / Freescale Semiconductor, MSC100ABIRM Datasheet - Page 25

• Manufacturer Part Number: MSC100ABIRM
• Description: SC100 Application Binary Interface Reference Manual
• Manufacturer: Motorola / Freescale Semiconductor

For return variables that do not fit in registers, the caller must reserve stack space. This return buffer area is
typically located with the local variables. This space is typically allocated only in functions that make calls
returning structures. Beyond these requirements, a function is free to manage its stack frame in any way
desired.
2.3.6 Frame and Argument Pointers
The ABI standard does not require the use of a frame pointer or an argument pointer. If, however, the use
of a frame pointer or an argument pointer is necessary, a compiler may allocate R7 as a frame pointer and
R6 as an argument pointer. When these registers are allocated for this purpose, they should be saved and
restored as part of the function prologue/epilog code.
SC100 Application Binary Interface
(High Addresses)
(Low Addresses)
Figure 2-2. Stack Frame Layout
Outgoing Parameters
Local Variables
Saved Registers
Return Address
Incoming Parameters
Preliminary (April 2000)
Function Calling Conventions
AA16
SP
2-7