Step-by-step explanation:
To determine how the arguments and results will be passed by the HCS12 C compiler, we need to consider the calling convention used by the compiler.
The HCS12 C compiler typically uses the "register-based" calling convention, also known as "fastcall". In this calling convention, some arguments are passed in registers and others are passed on the stack.
Here are the common rules for argument and result passing in the HCS12 C compiler:
1. Arguments passed in registers:
- The first argument is typically passed in the D register (D0).
- The second argument is typically passed in the X register (X).
- Remaining arguments are passed on the stack.
2. Result returned in registers:
- A single-byte result is returned in the A register (A).
- A larger result (such as a 16-bit or 32-bit integer) is returned in a combination of registers, generally A and B registers (A and B).
Based on the above rules, here's how the arguments and results will be passed in each function:
Function 1:
```c
void function1(int a, int b, int c);
```
- Arguments 'a', 'b', and 'c' will be passed on the stack.
- No result is returned (void).
Function 2:
```c
int function2(char a, int b, char c);
```
- Argument 'a' will be passed in the D register (D0), as it is a single-byte argument.
- Argument 'b' will be passed on the stack.
- Argument 'c' will be passed in the X register (X), as it is a single-byte argument.
- The result will be returned in the A register (A) as it is a single-byte result.
Function 3:
```c
float function3(double a, int b);
```
- Argument 'a' will be passed in the D registers (D0-D1), as it is a 64-bit argument.
- Argument 'b' will be passed on the stack.
- The result will be returned in the D registers (D0-D1) as it is a 64-bit result.
It's important to note that the specific implementation details may vary depending on the compiler version and compilation options used. It is advisable to consult the compiler documentation or generate and analyze the assembly output to ensure accurate understanding of the argument and result passing in a specific compiler setup.