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Owen wrote:OK, but how do you mangle a name provided without parameters?

void foo(void);

Owen wrote:You can't even mangle at the call site because there may be subtle mismatches (Int vs short vs char, etc) which will make it mangle incorrectly.

Owen wrote:Does the C standard even permit name mangling?

Owen wrote:And do you really want to implement some non-standard variant of C?

Combuster wrote:So the idiot who gets a linker error over a K&R function IMO deserves that title.

Combuster wrote:I'm a bit late with explaining the register distribution argument of last week

void foo(long a, long b, _____ , int u, int v); //assuming that u and v must be passed at the stack
{
    //u is at [R62 - 4] and v at [R62 - 8]
    PUSH.W   R61  //save the link-register
    PUSHM.W  R48,8 //save the registers R48 ... R55 (callee-save area)
    ADD.W   R62,100  //allocate 100 Bytes stack-frame
    //u is at [R62 - 140] and v at [R62 - 144] ; the stack-frame is at [R62 - 100] .... [R62 - 1]

    /* function code */

    SUB.W    R62,100  //free 100 Bytes stack-frame
    POPM.W  R48,8 //restore the registers R48 ... R55 (callee-save area)
    POP.W   R63  //restore the link-register direct into the instruction-pointer and do the RET
}

ErikVikinger wrote:I will use the following function header and footer (attention: my stack grows upwards)

Code: Select all

void foo(long a, long b, _____ , int u, int v); //assuming that u and v must be passed at the stack
{
    (...)
    PUSHM.W  R48,8 //save the registers R48 ... R55 (callee-save area)
    (...)
    POPM.W  R48,8 //restore the registers R48 ... R55 (callee-save area)
    (...)
}

This are in both places 3 instructions (that do not modify any other resources). Yes there exist dependencies with the stack-pointer (R62) but this are only 3 instructions and they must not be back-to-back.
I will create, extra for the function header and footer, 2 additional instructions ENTER and LEAVE that do this two jobs each in one instruction.

Owen wrote:One of the reasons I implement ENTER/LEAVE is because two stack ops back to back would cause the second instruction to stall for ...

Combuster wrote:You know that that wastes ...

ErikVikinger wrote:

js wrote: Some FPU's have similar regiser banks , If you want to know which, I can tell you once

Yes, please.

It has 24 user-accessible floating-point registers organized into three register banks. Three additional instructions (FSBP0, FSBP1, FSBP2) allow switching from one bank to another.