source: buchla-68k/lib700/jumpto.s@ 9bf0f86

| ------------------------------------------------------------------------------
| jumpto.s -- miscellaneous ROMP support functions
| Version 4 -- 1987-10-14 -- D.N. Lynx Crowe

|       WARNING:
|       --------
|               These functions, in general, assume supervisor mode and
|               'sane' arguments, so no error checking is done.

|       halt()

|               Brings the processor to a grinding halt.  Requires external
|               reset to restart things.  Use only for catastrophic hard halts.

|       jumpto(addr)
|       long addr;

|               Jumps to 'addr'.  No error check is done on 'addr'.

|       rjumpto(addr)
|       long addr;

|               Performs the 68000 'RESET' command, then jumps to 'addr'.
|               No error check is made on 'addr'.

|       sjumpto(addr, stack)
|       long addr, stack;

|               Sets a7 to 'stack', then jumps to 'addr'.
|               No error check is done on 'addr'.

|       xreset()

|               Performs the 68000 'RESET' command.  This is very dangerous,
|               and should be used with extreme care regarding such
|               things as interrupts, device initialization, vectors,
|               and sundry other reset-related things.

| ------------------------------------------------------------------------------
                .text

                .xdef   _halt,_jumpto,_rjumpto,_sjumpto,_xreset

                .page

_halt:          stop    #0x2700                 | stop dead, interrupts disabled
                jmp     _halt                   | stay stopped if stepped thru

_jumpto:        movea.l 4(a7),a0                | get jump address
                jmp     (a0)                    | go to the jump address

_rjumpto:       reset                           | reset external devices
                movea.l 4(a7),a0                | get jump address
                jmp     (a0)                    | go to the jump address

_sjumpto:       movea.l 4(a7),a0                | get jump address
                movea.l 8(a7),a7                | set stack pointer
                jmp     (a0)                    | go to the jump address

_xreset:        reset                           | reset external devices
                rts                             | return to caller

                .end