src/c/arch.h

   1 /* Architecture */
   2
   3 #ifndef __ARCH_H
   4 #define __ARCH_H
   5
   6 void initArchitecture(int stackSize, int regsCount);
   7
   8 /* Stack */
   9 extern int* stack;
  10 extern int sp;
  11 extern int fp;
  12
  13 void push(int x);
  14 int pop();
  15
  16 /* The stack when in a user procedure:
  17      fp -> |      |
  18            | fp   |  - the old fp (before this application)
  19            | ret  |  - return address
  20            | env  |  - points to the enviroment vector
  21            | n    |  - number of arguments
  22            | A0   |  - argument 0
  23            | A1   |  - argument 1
  24            | ...  |  - ...
  25            | An-1 |  - argument n-1
  26
  27    Note: sp does NOT have to be equal to fp - for example if we are in the
  28          middle of applying a procedure and already pushed some arguments
  29          on to the stack (then sp has changed, but fp has not).
  30
  31    Macros for user procedures:
  32 */
  33 #define ST_ARG(n) (stack[fp-5-(n)])
  34 #define ST_ARG_COUNT() (stack[fp-4])
  35 #define ST_OLDFP() (stack[fp-1])
  36 #define ST_RET() (stack[fp-2])
  37 #define ST_ENV() (stack[fp-3])
  38 #define RETURN() goto *pop()
  39
  40 /* General Purpose Registers */
  41 extern int* r;
  42 extern int r_res;
  43
  44 #endif