c64g.def

; georam, no payload in main memory

PAYLOAD	= $4100
HARNESS	= $1000
VMSADDR	= $1100
BAILOUT	= VMSADDR+0
DORTS	= VMSADDR+3
VMU	= VMSADDR+15

; cache the current page
curpage	= $02

; 6o6 configuration
; we present a full 64K address space and don't fault on stack, so we can
; be completely faultless

#define HELPINGS		1
#define HELPINGSALWAYS		1
#define FAULTLESS		1
#define	NO_SADDR_IN_FILE	1

; 6o6 defines

	; simulated register locations in zero page
	; these must be preserved between calls to the vm
areg	= $8b
xreg	= $8c
yreg	= $8d
preg	= $fb
sptr	= $fc
pc	= $fd	; and $fe

	; extra helpings mode
ehmode	= $a6

	; work area for memory access
dptr	= $8e	; and $8f

	; work area for instruction dispatch
hold0	= $9f
hold1	= $a5	; need not be configuous
abandon	= $9e	; save stack pointer if we abandon ship (protection fault?)

	; reserved work areas for the harness/kernel (if they want)
	; these should be contiguous
hhold0	= $be
hhold1	= $bf

; 6o6 return codes

#define	R_OK		0	/* all's well */
#define	R_BRK		1	/* break has occurred (replaces B flag) */
#define	R_MFAULT	2	/* memory fault propagated from harness */
#define R_BADINS	3	/* totally illegal instruction */
#define	R_UDI		4	/* user-defined (debug) irq -- check x for
					the passed parameter */
#define R_STACKUNDER	5	/* stack underflow, propagated from harness
					or dorts */
#define R_STACKOVER	6	/* stack overflow, same */