/* PDL *********************************************
BEGIN Stack
PUT started message
   PUSH 2 args onto stack
   CALL test function
   RESTORE stack
   PUT finished message
END
***************************************************/

/* Registers used **********************************
   a0, a1, d0
***************************************************/
              .NOLIST
              .INCLUDE  "..\\Include\\ASCII.i"
              .LIST

              .TEXT     1
StartMsg:     .ASCII    "Stack test start"
              .BYTE     CR, LF, 0

MidMsg:       .ASCIZ    "D0 arg is "

FinishMsg:    .ASCII    "Stack test end"
              .BYTE     CR, LF, 0

              .TEXT     0
              .GLOBAL   Stack

Stack:        lea       StartMsg, a0   | show starting
              jsr       PrintMsg

              pea       MidMsg         | set msg as arg
              move.w    #0x1234, d0    | set word
              move.w    d0,-(sp)       |  as another
              jsr       TestStack
              add.l     #6, sp         | correct stack

              lea       FinishMsg, a0  | show done
              jsr       PrintMsg
              rts                      | exit

/* PDL *********************************************
BEGIN TestStack
   SAVE registers
   SET stack frame
   COPY args to locals
   PUT string from arg
   PUT word from arg
   FREE stack frame
   RESTORE regs
END
***************************************************/

/* Registers not saved *****************************
   a0, d0
***************************************************/
TestStack:    movem.l   a1-a2/d1-d2,-(sp) | save regs
              link      a6,#-6             | set stack frame

/* Stack Frame details:
    a6 + 26   a0.l content from pea
    a6 + 24   d0.w content from move
    a6 + 20   return address.l from jsr
    a6 + 16   movem.l d2
    a6 + 12   movem.l d1
    a6 + 8    movem.l a2
    a6 + 4    movem.l a1
    a6 + 0    longword for a6
    a6 - 2    word for d0
    a6 - 6    longword for a0

              .EQU      ARG_A0,26         | 2 args
              .EQU      ARG_D0,24
              .EQU      VAR_A0,-6         | 2 locals
              .EQU      VAR_D0,-2

              move.l    (ARG_A0, a6), a0   | get longword arg
              move.l    a0, (VAR_A0, a6)   |  store as local
              move.w    (ARG_D0, a6), d0   | get word arg
              move.w    d0, (VAR_D0, a6)   |  store as local

              jsr       PrintMsg           | print string from arg
              move.b    #4, d1
              jsr       OutHex             | print word from arg
              jsr       NewLine            | be tidy

              unlk      a6                 | stack frame done
              movem.l   (sp)+, a1-a2/d1-d2 | restore regs
              rts                          | return