Random notes
------------

A random set of notes about sdcc and how it works.

Michael:
--------
Tracing parmBytes and function calls.

Bug:
void printf(const char *format);

void puts(const char *s)
{
	printf(s);
}

Generates the pseudo-code:
	  hl = s
	  push hl
	  call printf
	  pop l (not hl - so parmBytes is too small)

parmBytes for a function call seems to be setup in geniCodeCall in
SDCCicode.c.

geniCodeCall:
* Takes care of calls with side effects (?)
* Generates the icode to push the parameters (this also computes the 
  resulting stack size)
* Generates a CALL or PCALL depending on if its a function or pointer to.
* Computes the result
* Adds the code for the call to the chain.

My bug is probably in geniCodeParms - it's probably computing the
size of pointers wrong.

geniCodeParms:
* A 'parm' node causes this to be run on the tree branches.
* It switches on the stack mode and sendto mode, and adds the
  instructions required to push or put.
* A push adds the result of 'getSize' to the stack size.

So the bug is probably in getSize.  's' is not an aggregate, so the
bug is in getSize().

It seems that IS_SPEC() is being set, deferencing *s so that it's size
is sizeof(char) == 1.  It's either a SPECIFIER or a DECLARATOR - seems that
were the wrong way around.  This is set in SDCCsymt.c, SDCCval.c, and the 
yacc file. SDCCsymt.c and SDCCval.c havnt really changed in 5 days - must
be SDCC.y.  Nope, no changes.  diff against 5 days ago shows only intersting
changes are in SDCCicode.  Same with -14 days.