/* 8085 CALL, RET, RST and subroutine-linkage checks. */
kill(all)$
hexbyte(n) := printf(false,"~2,'0X",mod(n,256))$
hexword(n) := printf(false,"~4,'0X",mod(n,65536))$
hi(n) := floor(mod(n,65536)/256)$
lo(n) := mod(n,256)$

/* CALL 3400h located at 2050h. */
call_address : 8272$   /* 2050h */
target : 13312$        /* 3400h */
return_address : call_address+3$
sp0 : 16384$           /* 4000h */
sp_after : sp0-2$
printf(true,"CALL bytes: CD ~a ~a; return address=~a~%",
       hexbyte(lo(target)),hexbyte(hi(target)),hexword(return_address))$
printf(true,"Stack after CALL: [~a]=~a low, [~a]=~a high; SP=~a~%",
       hexword(sp_after),hexbyte(lo(return_address)),
       hexword(sp_after+1),hexbyte(hi(return_address)),hexword(sp_after))$

/* All eight software restart opcodes and vectors. */
for n:0 thru 7 do
  printf(true,"RST ~d: opcode=~a vector=~a~%",n,
         hexbyte(199+8*n),hexword(8*n))$

/* Code-size comparison. */
L : 40$
k : 4$
inline_bytes : k*L$
subroutine_bytes : L+3*k+1$
saving : inline_bytes-subroutine_bytes$
printf(true,"L=~d, k=~d: inline=~d bytes, subroutine=~d bytes, saving=~d bytes~%",
       L,k,inline_bytes,subroutine_bytes,saving)$

/* Stack depth: three active calls and five unmatched pair pushes. */
active_calls : 3$
active_pushes : 5$
depth : 2*(active_calls+active_pushes)$
printf(true,"Three calls plus five pair saves occupy ~d stack bytes.~%",depth)$