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2015-09-11T11:20:14Z

Wayne: Created page with " *************************************** * SYSCALL - a powerful subroutine for use with Basic09 * A special thanks to Robert Doggett for writing this routine. * * Basic09 ..."

2013-11-29T20:43:15Z

Created page with " *************************************** * SYSCALL - a powerful subroutine for use with Basic09 * A special thanks to Robert Doggett for writing this routine. * * Basic09 ..."

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***************************************
* SYSCALL - a powerful subroutine for use with Basic09
* A special thanks to Robert Doggett for writing this routine.
*
* Basic09 calling suquence:
* TYPE Registers=CC,A,B,DP:BYTE; X,Y,U:INTEGER
* DIM regs:Registers
*
* There is no DIM statement for code, which must be a BYTE or INTEGER value,
* and a non-DIM'd variable in Basic09 is either a type REAL or, with a $ as the
* last character of the name, a 32-character STRING.
* DIM code:BYTE
*
* RUN SysCall(code,registers)
*
* SysCall will allow you to execute ANY OS-9 System call from
* your Basic09 programs. BE WARNED!!! SysCall can be VERY
* dangerous, since it permits you to do things you may not want
* done during program execution (like format disks, write
* thousands of bytea all at once, and so on). However, it can
* also be very useful, IF you know what you are doing.
*
* NOTE: This version of SysCall will cause a Basic09 runtime
* error to occur if your system call returns an error. This can
* be easily overcome, as noted below. If you do this, you
* must check "regs.CC" to see if a system error has occurred.
*
* Here is an example of one possible use you may have for SysCall
*
* PROCEDURE filesize
* TYPE Registers=CC,A,B,DP:BYTE; X,Y,U:INTEGER
* DIM regs:Registers
* DIM path,callcode:BYTE \(* or INTEGER *)
* OPEN #path,"test":READ
* regs.A:=path
* regs.B:=2 \(* I$GetStt code *)
* RUN SysCall(callcode,regs)
* CLOSE #path
* PRINT USING "filesize = 0',2(h4)",regs.X; regs.U

USE /d0/defs/os9defs
opt 1

TYPE set SBRTN+ONJCT
REVS set REENT+1
mod SyCalEnd,SyCalNam,TYPE,REVS,SyCalEnt,0
SyCalNam fcs "SysCall"
fcb 2 edition number

E$Paras equ 56 Basic09's parameter error code
M.OS9 equ $103F OS-9 system call machine code
M.RTS equ $39 rts machine code

org 0 stacked variable
Return rmb 2 Return address
PCount rmb 2 number of params passed
Function rmb 4 OS-9 function code
Regs rmb 4 Register image

SyCalEnt ldd PCount,s Get parameter count
cmpd #2 exactly 2 parameters?
bne ParamErr abort if not
ldd Regs+2,s check size of register image
cmpd #10exactly 10 bytes?
bne ParamErr abort if not
ldd [Function,S] get os-9 function code
ldx Function+2,S get size of function param
leax -1,XINTEGER?
bne ParamErr abort if not
tfr B,A

* Now you build your OS9 call and return from subroutine on
* stack (A)=OS9 function call

SysCall ldb #M.RTS get "rts" machine code
pshs D
ldd #M.OS9 get OS-9 machine code
pshs D
ldu Regs+4,S get register image ptr
ldd R$D,U initialize regs for system call
ldx R$X,U
ldy R$Y,U
ldu R$U,U
jsr 0,S execute system call
pshs CC,Usave CC,U
ldu Regs+7,S
leau R$U,U
pshu A,B,DP,X,Y return unpdatd regs to caller
puls A,X get CC,U
sta ,-U
stx R$U,U
leas 4,S discard OS-9 call subroutine

* If you want to eliminate the possibility of a runtime error
* remove the comment designator (*) from the next line

* clrb
rts
ParamErr comb return carry set
ldb #E$Param Parameter error
rts

emod
SyCalEnd equ *

← Older revision		Revision as of 07:20, 11 September 2015
Line 103:		Line 103:
	emod		emod
	SyCalEnd equ *		SyCalEnd equ *

			[[Category:Programming]]
			[[Category:OS-9]]

SysCall.asm Level 1 - Revision history

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Wayne: Created page with " *************************************** * SYSCALL - a powerful subroutine for use with Basic09 * A special thanks to Robert Doggett for writing this routine. * * Basic09 ..."