ASM Routines

 BBS: Inland Empire Archive
Date: 05-12-92 (23:57)             Number: 3
From: MATT HART                    Refer#: NONE
  To: RICHARD VANNOY                Recvd: NO  
Subj: ASM Routines                   Conf: (2) Quik_Bas

 >RV> Let's say you have a PROC XYZ declared as
 >RV> DECLARE SUB XYZ(a%, b$)
 >RV> How does your assembly sub know where to find a% and b$?

Here's a MASM 5.0 or 6.0 example - assuming Near Strings

.model medium,basic
.code

PROC XYZ Aaddr:Word, Bdesc:Word
     ; Aaddr is the near address to a%
     ; Bdesc is the near pointer to the string descriptor for b$

     MOV  BX,Aaddr       ; BX has address to a%
     MOV  [BX],1000      ; Move 1000 into the address pointed to by BX
                         ; PRINT a% will show 1000

     MOV  SI,Bdesc       ; SI has address of descriptor for b$
     MOV  DS:[SI],AX     ; Move first 2 bytes at SI (string desc) into
                         ; AX - AX now has the string length
     MOV  DS:[SI+2],CL   ; Next 1 into CL - CL has first byte of the
                         ; string
     RET
XYZ EndP
END


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 * Origin: Midnight Micro!  V.32/REL  (918)451-3306 (1:170/600)