Interrupt 0Bh (Janus)

This is a brief Description of the janus code. This Code supports lowlevel access to the Janus system — the link between a PC and an Amiga.

THE PUBLIC ROUTINES	Name	ID	Description
1.Generation:	GETSERVICE1	0	not supported any more
	GETBASE	1	report segments, offset of janus mem
	ALLOCMEM	2	allocate janus memory
	FREEMEM	3	free janus memory
	SETPARAM	4	set pointer to service parameter
	SETSERVICE	5	not supported any more
	STOPSERVICE	6	not supported any more
	CALLAMIGA	7	call service on Amiga side
	WAITAMIGA	8	wait for service becomes ready
	CHECKAMIGA	9	check service status
2.Generation:	ADDSERVICE	10	add a dyn-service
	GETSERVICE	11	link to a dyn-service
	CALLSERVICE	12	call a dyn-service
	RELEASESERVICE	13	unlink from a dyn-service
	DELETESERVICE	14	delete a dyn-service
	LOCKSERVICEDATA	15	lock private mem of a dyn-service
	UNLOCKSERVICEDATA	16	unlock private mem of a dyn-service
	INITLOCK	17	Initialize a byte for use as a lock byte
	LOCKATTEMPT	18	Try once to obtain a Lock
	LOCK	19	Obtain a Lock
	UNLOCK	20	Release a Lock
	ALLOCJREMEMBER	21	Allocate Janus memory and link into a Remember list
	ATTACHJREMEMBER	22	Attach the list of one Janus memory key to another
	FREEJREMEMBER	23	Free memory allocated by calls to AllocJRemember()
	ALLOCSERVICEMEM	24	Allocate Janus memory linked to a ServiceData struct
	FREESERVICEMEM	25	Free mem added to a ServiceData by AllocServiceMem()

---

Service 0: JanusHandler/Get_service

NAME
Get_service -- Gets a new Service Number.

Expects	Return
AH =GETSERVICE1	AL = Status (JSERV_NOFUNCTION)

NOTES
Not Supported anymore

Service 1: JanusHandler/GetBase

NAME
GetBase -- Get the segment addresses and offsets for an old style service.

SYNOPSIS

• mov AH,GETBASE
• mov AL,Service_number
• int 0Bh

FUNCTION
Returns the segment address for buffer and parameter memory. Also returns the parameter memory offset for the old style service if defined.

Inputs	Result
AH = GETBASE	ES = Parameter memory segment
AL = Janus Service Number	DI = Parameter offset if defined, else -1
	DX = Buffer memory segment
	AL = Status return (JSERV_OK)

EXAMPLE

• mov AH,GETBASE
• mov AL,JSERV_AMIGASERVICE
• int 0Bh

---

Service 2: JanusHandler/AllocMem

NAME
AllocMem -- Allocate Janus memory.

SYNOPSIS

• mov AH,ALLOCMEM
• mov AL,Type
• mov BX,Size
• int 0Bh

FUNCTION
Allocates memory from the Janus dual-port RAM.

Inputs	Result
AH = ALLOCMEM	BX = Offset of allocated memory else 0
AL = Type of memory to allocate (MEMF_BUFFER, MEMF_PARAMETER)	AL = Status (JSERV_OK,JSERV_NOJANUSMEM)
BX = Number of bytes to allocate

EXAMPLE

• mov AH,ALLOCMEM
• mov AL,MEMF_BUFFER
• mov BX,200
• int 0Bh

SEE ALSO

• FreeMem()

---

Service 3: JanusHandler/FreeMem

NAME
FreeMem -- Free Janus memory previously allocated with AllocMem.

SYNOPSIS

• mov AH,FREEMEM
• mov AL,Type
• mov BX,Offset
• int 0bh

FUNCTION
Frees Janus dual-port memory previously allocated with AllocMem.

Inputs	Result
AH = FREEMEM	AL = Status (JSERV_OK, JSERV_NOJANUSMEM)
AL = Type of memory to free (MEMF_BUFFER, MEMF_PARAMETER)
BX = Offset of memory to free. (same value returned by AllocMem)

EXAMPLE

• mov AH,FREEMEM
• mov AL,MEMF_BUFFER
• mov BX,Offset
• int 0Bh

NOTES
Crashes if Type/Offset not valid!

SEE ALSO

• AllocMem()

---

Service 4: JanusHandler/SetParam

NAME
SetParam -- Set the parameter memory offset for an old style service.

SYNOPSIS

• mov AH,SETPARAM
• mov AL,ServiceNumber
• mov BX,Offset
• int 0Bh

FUNCTION
Sets the parameter memory pointer for the old style service to the offset given.

Inputs	Result
AH = SETPARAM	AL = Status (JSERV_OK)
AL = Janus Service Number
BX = Offset of parameter memory for this service)

EXAMPLE

• mov AH,SETPARAM
• mov AL,JSERV_AMIGASERVICE
• mov BX,Offset
• int 0Bh

NOTES
This is a low level Janus call retained for compatibility with V1.0.
Service programmers should not use this function.

---

Service 5: JanusHandler/SetService

NAME
SetService -- Set an address for a far call for that service.

Inputs	Result
AH = SETSERVICE	AL = Status (JSERV_NOFUNCTION)
AL = Janus Service Number
ES:DX = Entry address for FAR call

NOTES
Not Supported anymore

---

Service 6: JanusHandler/StopService

NAME
StopService -- Prevents AMIGA from using the far call (see above) for this function and releases this Service Number. No memory is freed up. No calls are accepted from either side anymore.

Inputs	Result
AH = STOPSERVICE	AL = Status (JSERV_NOFUNCTION)
AL = Number of Service to stop

NOTES

• Not Supported anymore

---

Service 7: JanusHandler/CallAmiga

NAME
CallAmiga -- Call an old style service.

SYNOPSIS

• mov AH,Function
• mov AL,Service_Number
• int 0Bh

FUNCTION

• Signals the Amiga side of the given old style service.

Inputs	Result
AH =CALLAMIGA	AL = Status (JSERV_PENDING, JSERV_FINISHED, JSERV_NOSERVICE)
AL = Janus Service Number

EXAMPLE

• mov AH,CALLAMIGA
• mov AL,JSERV_AMIGASERVICE
• int 0Bh

NOTES

• This is a low level Janus call retained for compatibility with V1.0. Service programmers should not use this function.

---

Service 8: JanusHandler/WaitAmiga

NAME
WaitAmiga -- Wait for a previously issued CallAmiga to complete.

SYNOPSIS

• mov AH,Function
• mov AL,Service_Number
• int 0Bh

FUNCTION

• Waits for the Amiga to respond to the last CallAmiga.

Inputs	Result
AH = WAITAMIGA	AL = Status (JSERV_FINISHED, JSERV_NOSERVICE)
AL = Janus Service Number

EXAMPLE

• mov AH,WAITAMIGA
• mov AL,JSERV_AMIGASERVICE
• int 0Bh

NOTES

• This is a low level Janus call retained for compatibility with V1.0. Service programmers should not use this function.

---

Service 9: JanusHandler/CheckAmiga

NAME
CheckAmiga -- Check the status of a previously issued CallAmiga.

SYNOPSIS

• mov AH,Function
• mov AL,Service_Number
• int 0Bh

FUNCTION

• Checks the response status of the last CallAmiga.

Inputs	Result
AH = CHECKAMIGA	AL = Status (JSERV_PENDING, JSERV_FINISHED, JSERV_NOSERVICE)
AL = Janus Service Number

EXAMPLE

• mov AH,CHECKAMIGA
• mov AL,JSERV_AMIGASERVICE
• int 0Bh

NOTES

• This is a low level Janus call retained for compatibility with V1.0. Service programmers should not use this function.

---

Service 10: JanusHandler/AddService

NAME
AddService -- Add a service to the system.

SYNOPSIS

• mov AH,ADDSERVICE
• mov DS,ApplicationID_high_word
• mov SI,ApplicationID_low_word
• mov CX,LocalID
• mov BX,Size
• mov DX,Type
• mov AL,Flags
• mov ES,Handler_Segment
• mov DI,Handler_Offset
• int 0Bh

FUNCTION
Adds a service to the system.

Inputs	Result
AH = ADDSERVICE	AL = Status (JSERV_OK, JSERV_NOJANUSMEM, JSERV_NOSERVICE,JSERV_NOJANUSBASE)
DS = High word of 32 bit application ID	ES = Segment of ServiceData structure
SI = Low word of application ID	DI = Offset of ServiceData structure
CX = Local ID
BX = Size in bytes of memory to allocate
DX = Type of memory to allocate (MEMF_BUFFER, MEMF_PARAMETER)
AL = AddService flags from services.[hi]
ES = Segment of assembly language routine to call when this service is called or NULL.
DI = Offset of assembly language routine to call when this service is called or NULL.

EXAMPLE

• mov AH,ADDSERVICE
• mov DS,ApplicationID_high_word
• mov SI,ApplicationID_low_word
• mov CX,LocalID
• mov BX,Size
• mov DX,MEMF_BUFFER
• mov AL,ADDS_EXCLUSIVE | ADDS_TOAMIGA_ONLY
• mov ES,Handler_Segment
• mov DI,Handler_Offset
• int 0Bh

SEE ALSO

• CallService()
• DeleteService()
• GetService()
• ReleaseService()

---

Service 11: JanusHandler/GetService

NAME
GetService -- Get a service and its ServiceData pointer

SYNOPSIS

• mov AH,GETSERVICE
• mov DS,ApplicationID_high_word
• mov SI,ApplicationID_low_word
• mov CX,LocalID
• mov AL,Flags
• mov ES,Handler_Segment
• mov DI,Handler_Offset
• int 0Bh

FUNCTION
Gets a pointer to a Services ServiceData structure if the Service exists.

Inputs	Result
AH = GETSERVICE
DS = High word of 32bit application ID	AL = Status (JSERV_OK, JSERV_NOSERVICE)
SI = Low word of 32bit application ID	ES = Segment of ServiceData structure
CX = Local ID	DI = Offset of ServiceData structure
AL = Flags
ES = Segment of assembly language handler to be called whenever this service is called or NULL.
DI = Offset of assembly language handler to be called whenever this service is called or NULL.

EXAMPLE

• mov ax,ApplicationID_high_word
• mov DS,ax
• mov SI,ApplicationID_low_word
• mov CX,LocalID
• mov ax,Handler_Segment
• mov ES,ax
• mov DI,Handler_Offset
• mov AH,GETSERVICE
• mov AL,GETS_WAIT
• int 0Bh

SEE ALSO

• AddService()
• CallService()
• DeleteService()
• ReleaseService()

---

Service 12: JanusHandler/CallService

NAME
CallService -- Signal all other users of a service.

SYNOPSIS

• mov AH,Function
• mov DI,ServiceData_Offset
• int 0Bh

FUNCTION
To signal all users of a service except the one that called CallService.

Inputs	Result
AH = CALLSERVICE
DI = Offset of the services ServiceData structure.	AL = Status (JSERV_OK, JSERV_NOJANUSMEM, JSERV_NOJANUSBASE)

EXAMPLE

• mov AH,CALLSERVICE
• mov DI,ServiceData_Offset
• int 0Bh

SEE ALSO

• AddService()
• DeleteService()
• GetService()
• ReleaseService()

---

Service 13: JanusHandler/ReleaseService

NAME
ReleaseService -- Release a service previously obtained with GetService

SYNOPSIS

• mov AH,RELEASESERVICE
• mov DI,ServiceData_Offset
• int 0Bh

FUNCTION
To Release use of a service previously gotten via GetService.

Inputs	Result
AH = RELEASESERVICE
DI = Offset of ServiceData structure.	AL = Status (JSERV_OK, JSERV_NOJANUSBASE)

EXAMPLE

• mov AH,RELEASESERVICE
• mov DI,ServiceData_Offset
• int 0Bh

SEE ALSO

• AddService()
• CallService()
• DeleteService()
• GetService()

---

Service 14: JanusHandler/DeleteService

NAME
DeleteService -- Delete a service previously added with AddService

SYNOPSIS

• mov AH,,DELETESERVICE
• mov DI,ServiceData_Offset
• int 0Bh

FUNCTION
To Delete a service previously added with AddService.

Inputs	Result
AH = ,DELETESERVICE
DI = Offset of ServiceData structure.	AL = Status (JSERV_OK, JSERV_NOJANUSBASE)

EXAMPLE

• mov AH,DELETESERVICE
• mov DI,ServiceData_Offset
• int 0Bh

SEE ALSO

• AddService()
• CallService()
• GetService()
• ReleaseService()

---

Service 15: JanusHandler/LockServiceData

NAME
LockServiceData -- Perform the steps necessary to Lock a ServiceData structure.

SYNOPSIS

• mov AH,LOCKSERVICEDATA
• mov DI,ServiceData_Offset
• int 0Bh

FUNCTION
Performs the necessary steps to Lock a ServiceData structure for exclusive access.

Inputs	Result
AH = LOCKSERVICEDATA
DI = Offset of ServiceData structure.	AL = Status (JSERV_OK)

EXAMPLE

• mov AH,LOCKSERVICEDATA
• mov DI,ServiceData_Offset
• int 0Bh

SEE ALSO

• UnlockServiceData()

---

Service 16: JanusHandler/UnLockServiceData

NAME
UnLockServiceData -- Perform the steps necessary to UnLock a ServiceData structure.

SYNOPSIS

• mov AH,UnLockServiceData
• mov DI,ServiceData_Offset
• int 0Bh

FUNCTION
Performs the necessary steps to UnLock a ServiceData structure.

Inputs	Result
AH = UNLOCKSERVICEDATA
DI = Offset of ServiceData structure.	AL = Status (JSERV_OK)

EXAMPLE

• mov AH,UNLOCKSERVICEDATA
• mov DI,ServiceData_Offset
• int 0Bh

SEE ALSO

• LockServiceData()

---

Service 17: JanusHandler/InitLock

NAME
JanusInitLock -- Initialize a byte for use as a lock byte.

SYNOPSIS

• mov AH,INITLOCK
• mov ES,Segment
• mov DI,Offset
• int 0Bh

FUNCTION
Performs the necessary steps to Initialize a Janus Lock byte.

Inputs	Result
AH = INITLOCK	The Lock byte is initialized.
ES = Segment of lock byte.
DI = Offset of lock byte

RESULT
The Lock byte is initialized.

EXAMPLE

• mov AH,INITLOCK
• mov ES,Segment
• mov DI,Offset
• int 0Bh

SEE ALSO

• LockAttempt()
• Lock()
• Unlock()

---

Service 18: JanusHandler/LockAttempt

NAME
JanusLockAttempt -- Try once to obtain a Lock

SYNOPSIS

• mov AH,LOCKATTEMPT
• mov ES,Segment
• mov DI,Offset
• int 0Bh

FUNCTION
Attempts once to gain a Lock.

Inputs	Result
AH = LOCKATTEMPT	AL = TRUE if lock is gotten FALSE otherwise.
ES = Segment of lock byte.
DI = Offset of lock byte

EXAMPLE

• mov AH,LOCKATTEMPT
• mov ES,Segment
• mov DI,Offset
• int 0Bh

SEE ALSO

• InitLock()
• Lock()
• Unlock()

---

Service 19: JanusHandler/Lock

NAME
JanusLock -- Obtain a Lock

SYNOPSIS

• mov AH,LOCK
• mov ES,Segment
• mov DI,Offset
• int 0Bh

FUNCTION
Get a lock.

Inputs	Result
AH = LOCK	Returns when the lock is gotten.
ES = Segment of lock byte.
DI = Offset of lock byte

EXAMPLE

• mov AH,LOCK
• mov ES,Segment
• mov DI,Offset
• int 0Bh

SEE ALSO

• InitLock()
• LockAttempt()
• Unlock()

---

Service 20: JanusHandler/Unlock

NAME
JanusUnlock -- Release a Lock

SYNOPSIS

• mov AH,UNLOCK
• mov ES,Segment
• mov DI,Offset
• int 0Bh

FUNCTION
Release a lock.

Inputs	Result
AH = UNLOCK	Returns when the lock is released.
ES = Segment of lock byte.
DI = Offset of lock byte

EXAMPLE

• mov AH,UNLOCK
• mov ES,Segment
• mov DI,Offset
• int 0Bh

SEE ALSO

• InitLock()
• LockAttempt()
• Lock()

---

Service 21: JanusHandler/AllocJRemember

NAME
AllocJRemember -- Allocate Janus memory and link into a Remember list

SYNOPSIS

• mov AH,ALLOCJREMEMBER
• mov AL,Type
• mov BX,Size
• mov ES,JRememberKey_Segment
• mov DI,JRememberKey_Offset
• int 0Bh

FUNCTION
Allocates memory from the Janus dual-port RAM, but also adds the details of the allocation into a master list so that you make just one call the FreeJRemember() routine at a later time to free all the memory you allocated.

Inputs	Result
AH = ALLOCJREMEMBER	BX = Offset of allocated memory else 0
AL = Type of memory to allocate (MEMF_BUFFER, MEMF_PARAMETER)	AL = Status (JSERV_OK,JSERV_NOJANUSMEM)
BX = Number of bytes to allocate
DI = Offset of JRememberKey (Before your very first call to AllocJRemember() the pointer should be set to NULL.)

EXAMPLE

• mov AH,ALLOCJREMEMBER
• mov AL,MEMF_BUFFER
• mov BX,200
• mov ES,JRememberKey_Segment
• mov DI,JRememberKey_Offset
• int 0Bh

SEE ALSO

• AttachJRemember()
• FreeJRemember()

---

Service 22: JanusHandler/AttachJRemember

NAME
AttachJRemember -- Attach the list of one Janus memory key to another

SYNOPSIS

• mov AH,ATTACHJREMEMBER
• mov ES,To_JRememberKey_Segment
• mov DI,To_JRememberKey_Offset
• mov DS,From_JRememberKey_Segment
• mov SI,From_JRememberKey_Offset
• int 0Bh

FUNCTION
This routine accepts two Janus RememberKeys created by calls to AllocJRemember() and attaches the contents of the FromKey to the ToKey. In the process, FromKey is set equal to NULL.

Inputs	Result
AH = ATTACHJREMEMBER	None
ES = Segment of To_JRememberKey
DI = Offset of To_JRememberKey (address of a pointer to JanusRemember structures, which pointer is going to receive the list pointed to by FromKey)
DS = Segment of From_JRememberKey
SI = Offset of From_JRememberKey ( address of a pointer to JanusRemember structures, which pointer has the list that's going to be attached ToKey, after which the FromKey variable will be set to NULL.)

SEE ALSO

• AllocJRemember()
• FreeJRemember()

---

Service 23: JanusHandler/FreeJRemember

NAME
FreeJRemember -- Free memory allocated by calls to AllocJRemember()

SYNOPSIS

• mov AH,Function
• mov AL,ReallyForget
• mov ES,JRememberKey_Segment
• movDI,JRememberKey_Offset
• int 0Bh

FUNCTION
This function frees up Janus memory allocated by the AllocJRemember() function.
It will either free up just the JanusRemember structures(ReallyForget = FALSE), which supply the link nodes that tie your allocations together,
or it will deallocate both the link nodes AND your memory buffers too (ReallyForget = TRUE).

Inputs	Result
AH = FREEJREMEMBER	None
AL = ReallyForget (BOOL) (a BOOL FALSE or TRUE describing, respectively, whether you want to free up only the Remember nodes or if you want this procedure to really forget about all of the memory, including both the nodes and the memory buffers pointed to by the nodes.)
ES = Segment of JRememberKey
DI = Offset of JRememberKey (the address of a pointer to struct JanusRemember. This pointer should either be NULL or set to some value (possibly NULL) by a call to AllocRemember()

SEE ALSO

• AllocJRemember()
• AttachJRemember()

---

Service 24: JanusHandler/AllocServiceMem

NAME
AllocServiceMem -- Allocate Janus memory linked to a ServiceData struct

SYNOPSIS

• mov AH,ALLOCSERVICEMEM
• mov AL,Type
• mov BX,Size
• mov DI,ServiceData_Offset
• int 0Bh

FUNCTION
This routine allocates memory for you and records the details of the allocation in the specified ServiceData structure. This memory, unless you free it explicitly with a call to FreeServiceMem(), will be automatically freed when the service is deleted and removed from the system.

Inputs	Result
AH = ALLOCSERVICEMEM	BX = Offset of allocated memory else 0
AL = Type of memory to allocate (MEMF_BUFFER, MEMF_PARAMETER)	AL = Status (JSERV_OK,JSERV_NOJANUSMEM)
BX = Number of bytes to allocate
DI = Offset of ServiceData structure

SEE ALSO

• FreeServiceMem()

---

Service 25: JanusHandler/FreeServiceMem

NAME
FreeServiceMem -- Free mem added to a ServiceData by AllocServiceMem()

SYNOPSIS

• SYNOPSIS
• mov AH,FREESERVICEMEM
• mov AL,Type
• mov BX,ServiceMem_Offset
• mov DI,ServiceData_Offset
• int 0Bh

FUNCTION
This routine frees memory that had been allocated with a call to AllocServiceMem(). You can choose to free a single block of memory or all the memory of the ServiceData structure.

Inputs	Result
AH = FREESERVICEMEM	None
AL = Type of memory to allocate (MEMF_BUFFER, MEMF_PARAMETER)
BX = Offset of prior allocated memory or NULL if you want to delete all of the ServiceData's memory
DI = Offset of ServiceData structure

SEE ALSO

• AllocServiceMem()

Last Update: 20.06.2022