| /* |
| * mvme162lx-asm.S -- assembler routines for the MVME stub. |
| * |
| * This code was pulled out of mvme162lx-stub.c by Ian Taylor so that I |
| * could handle different register and label prefixes in a sensible |
| * way. |
| */ |
| |
| /**************************************************************************** |
| |
| THIS SOFTWARE IS NOT COPYRIGHTED |
| |
| HP offers the following for use in the public domain. HP makes no |
| warranty with regard to the software or it's performance and the |
| user accepts the software "AS IS" with all faults. |
| |
| HP DISCLAIMS ANY WARRANTIES, EXPRESS OR IMPLIED, WITH REGARD |
| TO THIS SOFTWARE INCLUDING BUT NOT LIMITED TO THE WARRANTIES |
| OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. |
| |
| ****************************************************************************/ |
| |
| #include "asm.h" |
| |
| .title "mvme162lx-asm.S for m68k" |
| |
| .globl SYM (registers) |
| .globl SYM (lastFrame) |
| .globl SYM (superStack) |
| .globl SYM (exceptionHook) |
| .globl SYM (_returnFromException) |
| .globl SYM (stackPtr) |
| .globl SYM (handle_exception) |
| .globl SYM (exceptionSize) |
| |
| .text |
| .globl SYM (return_to_super) |
| SYM (return_to_super): |
| movel SYM (registers)+60,sp /* get new stack pointer */ |
| movel SYM (lastFrame),a0 /* get last frame info */ |
| bra return_to_any |
| |
| .globl SYM (return_to_user) |
| SYM (return_to_user): |
| movel SYM (registers)+60,a0 /* get usp */ |
| movel a0,usp /* set usp */ |
| movel SYM (superStack),sp /* get original stack pointer */ |
| |
| return_to_any: |
| movel SYM (lastFrame),a0 /* get last frame info */ |
| movel a0@+,SYM (lastFrame) /* link in previous frame */ |
| addql IMM (8),a0 /* skip over pc, vector#*/ |
| movew a0@+,d0 /* get # of words in cpu frame */ |
| addw d0,a0 /* point to end of data */ |
| addw d0,a0 /* point to end of data */ |
| movel a0,a1 |
| /* copy the stack frame */ |
| subql IMM (1),d0 |
| copyUserLoop: |
| movew a1@-,sp@- |
| dbf d0,copyUserLoop |
| |
| #ifdef __HAVE_68881__ |
| fmoveml SYM (registers)+168,fpcr/fpsr/fpi |
| fmovemx SYM (registers)+72,fp0-fp7 |
| cmpl IMM (-1),a0@ /* skip frestore flag set ? */ |
| beq skip_frestore |
| frestore a0@+ |
| skip_frestore: |
| #endif |
| |
| moveml SYM (registers),d0-d7/a0-a6 |
| rte /* pop and go! */ |
| |
| |
| /* this function is called immediately when a level 7 interrupt occurs */ |
| /* if the previous interrupt level was 7 then we're already servicing */ |
| /* this interrupt and an rte is in order to return to the debugger. */ |
| /* For the 68000, the offset for sr is 6 due to the jsr return address */ |
| .text |
| .globl SYM (_debug_level7) |
| SYM (_debug_level7): |
| movew d0,sp@- |
| #ifdef mc68020 |
| movew sp@(2),d0 |
| #else |
| movew sp@(6),d0 |
| #endif |
| andiw IMM (0x700),d0 |
| cmpiw IMM (0x700),d0 |
| beq _already7 |
| movew sp@+,d0 |
| bra SYM (_catchException) |
| _already7: |
| movew sp@+,d0 |
| #ifndef mc68020 |
| lea sp@(4),sp /* pull off 68000 return address */ |
| #endif |
| rte |
| |
| #ifdef mc68020 |
| /* This function is called when a 68020 exception occurs. It saves |
| * all the cpu and fpcp regs in the _registers array, creates a frame on a |
| * linked list of frames which has the cpu and fpcp stack frames needed |
| * to properly restore the context of these processors, and invokes |
| * an exception handler (remcom_handler). |
| * |
| * stack on entry: stack on exit: |
| * N bytes of junk exception # MSWord |
| * Exception Format Word exception # MSWord |
| * Program counter LSWord |
| * Program counter MSWord |
| * Status Register |
| * |
| * |
| */ |
| |
| .text |
| .globl SYM (_catchException) |
| SYM (_catchException): |
| |
| oriw IMM (0x0700),sr /* Disable interrupts */ |
| |
| moveml d0-d7/a0-a6,SYM (registers) /* save registers */ |
| movel SYM (lastFrame),a0 /* last frame pointer */ |
| |
| #ifdef __HAVE_68881__ |
| /* do an fsave, then remember the address to begin a restore from */ |
| fsave a0@- |
| fmovemx fp0-fp7, SYM (registers)+72 |
| fmoveml fpcr/fpsr/fpi, SYM (registers)+168 |
| #endif |
| |
| lea SYM (registers),a5 /* get address of registers */ |
| movew sp@,d1 /* get status register */ |
| movew d1,a5@(66) /* save sr */ |
| movel sp@(2),a4 /* save pc in a4 for later use */ |
| movel a4,a5@(68) /* save pc in _regisers[] */ |
| |
| /* figure out how many bytes in the stack frame */ |
| movew sp@(6),d0 /* get '020 exception format */ |
| movew d0,d2 /* make a copy of format word */ |
| andiw IMM (0xf000),d0 /* mask off format type */ |
| rolw IMM (5),d0 /* rotate into the low byte *2 */ |
| lea SYM (exceptionSize),a1 |
| addw d0,a1 /* index into the table */ |
| movew a1@,d0 /* get number of words in frame */ |
| movew d0,d3 /* save it */ |
| subw d0,a0 /* adjust save pointer */ |
| subw d0,a0 /* adjust save pointer(bytes) */ |
| movel a0,a1 /* copy save pointer */ |
| subql IMM (1),d0 /* predecrement loop counter */ |
| |
| /* copy the frame */ |
| |
| saveFrameLoop: |
| movew sp@+,a1@+ |
| dbf d0,saveFrameLoop |
| |
| /* now that the stack has been clenaed, |
| * save the a7 in use at time of exception |
| */ |
| movel sp,SYM (superStack) /* save supervisor sp */ |
| andiw IMM (0x2000),d1 /* were we in supervisor mode ? */ |
| beq userMode |
| movel a7,a5@(60) /* save a7 */ |
| bra a7saveDone |
| userMode: |
| movel usp,a1 |
| movel a1,a5@(60) /* save user stack pointer */ |
| a7saveDone: |
| |
| |
| /* save size of frame */ |
| movew d3,a0@- |
| |
| /* compute exception number */ |
| andl IMM (0xfff),d2 /* mask off vector offset */ |
| lsrw IMM (2),d2 /* divide by 4 to get vect num */ |
| movel d2,a0@- /* save it */ |
| |
| /* save pc causing exception */ |
| movel a4,a0@- |
| |
| /* save old frame link and set the new value*/ |
| movel SYM (lastFrame),a1 /* last frame pointer */ |
| movel a1,a0@- /* save pointer to prev frame */ |
| movel a0,SYM (lastFrame) |
| |
| movel d2,sp@- /* push exception num */ |
| #ifdef TMP_HACK |
| movel SYM (exceptionHook),a0 /* get address of handler */ |
| jbsr a0@ /* and call it */ |
| #else |
| jbsr SYM (remcomHandler) |
| #endif |
| clrl sp@ /* replace exception num parm with frame ptr */ |
| jbsr SYM (_returnFromException) /* jbsr, but never returns */ |
| |
| #else /* mc68000 */ |
| |
| /* This function is called when an exception occurs. It translates the |
| * return address found on the stack into an exception vector # which |
| * is then handled by either handle_exception or a system handler. |
| * _catchException provides a front end for both. |
| * |
| * stack on entry: stack on exit: |
| * Program counter MSWord exception # MSWord |
| * Program counter LSWord exception # MSWord |
| * Status Register |
| * Return Address MSWord |
| * Return Address LSWord |
| */ |
| .text |
| .globl SYM (_catchException) |
| SYM (_catchException): |
| |
| oriw IMM (0x0700),sr /* Disable interrupts */ |
| |
| moveml d0-d7/a0-a6,SYM (registers) /* save registers */ |
| movel SYM (lastFrame),a0 /* last frame pointer */ |
| |
| #ifdef __HAVE_68881__ |
| /* do an fsave, then remember the address to begin a restore from */ |
| fsave a0@- |
| fmovemx fp0-fp7, SYM (registers)+72 |
| fmoveml fpcr/fpsr/fpi, SYM (registers)+168 |
| #endif |
| |
| lea SYM (registers),a5 /* get address of registers */ |
| movel sp@+,d2 /* pop return address */ |
| addl IMM (1530),d2 /* convert return addr to */ |
| divs IMM (6),d2 /* exception number */ |
| extl d2 |
| |
| moveql IMM (3),d3 /* assume a three word frame */ |
| |
| cmpiw IMM (3),d2 /* bus error or address error ? */ |
| bgt normal /* if >3 then normal error */ |
| movel sp@+,a0@- /* copy error info to frame buff*/ |
| movel sp@+,a0@- /* these are never used */ |
| moveql IMM (7),d3 /* this is a 7 word frame */ |
| |
| normal: |
| movew sp@+,d1 /* pop status register */ |
| movel sp@+,a4 /* pop program counter */ |
| movew d1,a5@(66) /* save sr */ |
| movel a4,a5@(68) /* save pc in _regisers[] */ |
| movel a4,a0@- /* copy pc to frame buffer */ |
| movew d1,a0@- /* copy sr to frame buffer */ |
| |
| movel sp,SYM (superStack) /* save supervisor sp */ |
| |
| andiw IMM (0x2000),d1 /* were we in supervisor mode ? */ |
| beq userMode |
| movel a7,a5@(60) /* save a7 */ |
| bra saveDone |
| userMode: |
| movel usp,a1 /* save user stack pointer */ |
| movel a1,a5@(60) /* save user stack pointer */ |
| saveDone: |
| |
| movew d3,a0@- /* push frame size in words */ |
| movel d2,a0@- /* push vector number */ |
| movel a4,a0@- /* push exception pc */ |
| |
| /* save old frame link and set the new value */ |
| movel SYM (lastFrame),a1 /* last frame pointer */ |
| movel a1,a0@- /* save pointer to prev frame */ |
| movel a0,SYM (lastFrame) |
| |
| movel d2,sp@- /* push exception num */ |
| movel SYM (exceptionHook),a0 /* get address of handler */ |
| jbsr a0@ /* and call it */ |
| clrl sp@ /* replace exception num parm with frame ptr */ |
| jbsr SYM (_returnFromException) /* jbsr, but never returns */ |
| |
| #endif /* m68000 */ |
| |
| /* |
| * remcomHandler is a front end for handle_exception. It moves the |
| * stack pointer into an area reserved for debugger use in case the |
| * breakpoint happened in supervisor mode. |
| */ |
| .globl SYM (remcomHandler) |
| SYM (remcomHandler): |
| addl IMM (4),sp /* pop off return address */ |
| movel sp@+,d0 /* get the exception number */ |
| movel SYM (stackPtr),sp /* move to remcom stack area */ |
| movel d0,sp@- /* push exception onto stack */ |
| jbsr SYM (handle_exception) /* this never returns */ |
| rts /* return */ |
