diff options
Diffstat (limited to 'c/src/lib/libcpu/m68k/m68040/fpsp/rtems_skel.s')
| -rw-r--r-- | c/src/lib/libcpu/m68k/m68040/fpsp/rtems_skel.s | 397 |
1 files changed, 397 insertions, 0 deletions
diff --git a/c/src/lib/libcpu/m68k/m68040/fpsp/rtems_skel.s b/c/src/lib/libcpu/m68k/m68040/fpsp/rtems_skel.s new file mode 100644 index 0000000000..a347f5cee4 --- /dev/null +++ b/c/src/lib/libcpu/m68k/m68040/fpsp/rtems_skel.s @@ -0,0 +1,397 @@ +// +// skeleton.sa 3.2 4/26/91 +// +// This file contains code that is system dependent and will +// need to be modified to install the FPSP. +// +// Each entry point for exception 'xxxx' begins with a 'jmp fpsp_xxxx'. +// Put any target system specific handling that must be done immediately +// before the jump instruction. If there no handling necessary, then +// the 'fpsp_xxxx' handler entry point should be placed in the exception +// table so that the 'jmp' can be eliminated. If the FPSP determines that the +// exception is one that must be reported then there will be a +// return from the package by a 'jmp real_xxxx'. At that point +// the machine state will be identical to the state before +// the FPSP was entered. In particular, whatever condition +// that caused the exception will still be pending when the FPSP +// package returns. Thus, there will be system specific code +// to handle the exception. +// +// If the exception was completely handled by the package, then +// the return will be via a 'jmp fpsp_done'. Unless there is +// OS specific work to be done (such as handling a context switch or +// interrupt) the user program can be resumed via 'rte'. +// +// In the following skeleton code, some typical 'real_xxxx' handling +// code is shown. This code may need to be moved to an appropriate +// place in the target system, or rewritten. +// + +// Copyright (C) Motorola, Inc. 1990 +// All Rights Reserved +// +// THIS IS UNPUBLISHED PROPRIETARY SOURCE CODE OF MOTOROLA +// The copyright notice above does not evidence any +// actual or intended publication of such source code. + +// $Id$ + +// +// Modified for Linux-1.3.x by Jes Sorensen (jds@kom.auc.dk) +// Modified for RTEMS 4.0.0 by Eric Norum (eric@skatter.usask.ca) +// + +#include <asm.h> + +//SKELETON idnt 2,1 | Motorola 040 Floating Point Software Package + + .include "fpsp.defs" + +// +// Divide by Zero exception +// +// All dz exceptions are 'real', hence no fpsp_dz entry point. +// + .global SYM(_fpspEntry_dz) +SYM(_fpspEntry_dz): + link %a6,#-LOCAL_SIZE + fsave -(%sp) + bclrb #E1,E_BYTE(%a6) + frestore (%sp)+ + unlk %a6 + jmp ([SYM(M68040FPSPUserExceptionHandlers)+3*4],za0) + +// +// Inexact exception +// +// All inexact exceptions are real, but the 'real' handler +// will probably want to clear the pending exception. +// The provided code will clear the E3 exception (if pending), +// otherwise clear the E1 exception. The frestore is not really +// necessary for E1 exceptions. +// +// Code following the 'inex' label is to handle bug #1232. In this +// bug, if an E1 snan, ovfl, or unfl occurred, and the process was +// swapped out before taking the exception, the exception taken on +// return was inex, rather than the correct exception. The snan, ovfl, +// and unfl exception to be taken must not have been enabled. The +// fix is to check for E1, and the existence of one of snan, ovfl, +// or unfl bits set in the fpsr. If any of these are set, branch +// to the appropriate handler for the exception in the fpsr. Note +// that this fix is only for d43b parts, and is skipped if the +// version number is not $40. +// +// + .global SYM(_fpspEntry_inex) + .global real_inex +SYM(_fpspEntry_inex): + link %a6,#-LOCAL_SIZE + fsave -(%sp) + cmpib #VER_40,(%sp) //test version number + bnes not_fmt40 + fmovel %fpsr,-(%sp) + btstb #E1,E_BYTE(%a6) //test for E1 set + beqs not_b1232 + btstb #snan_bit,2(%sp) //test for snan + beq inex_ckofl + addl #4,%sp + frestore (%sp)+ + unlk %a6 + bra snan +inex_ckofl: + btstb #ovfl_bit,2(%sp) //test for ovfl + beq inex_ckufl + addl #4,%sp + frestore (%sp)+ + unlk %a6 + bra SYM(_fpspEntry_ovfl) +inex_ckufl: + btstb #unfl_bit,2(%sp) //test for unfl + beq not_b1232 + addl #4,%sp + frestore (%sp)+ + unlk %a6 + bra SYM(_fpspEntry_unfl) + +// +// We do not have the bug 1232 case. Clean up the stack and call +// real_inex. +// +not_b1232: + addl #4,%sp + frestore (%sp)+ + unlk %a6 + +real_inex: + link %a6,#-LOCAL_SIZE + fsave -(%sp) +not_fmt40: + bclrb #E3,E_BYTE(%a6) //clear and test E3 flag + beqs inex_cke1 +// +// Clear dirty bit on dest resister in the frame before branching +// to b1238_fix. +// + moveml %d0/%d1,USER_DA(%a6) + bfextu CMDREG1B(%a6){#6:#3},%d0 //get dest reg no + bclrb %d0,FPR_DIRTY_BITS(%a6) //clr dest dirty bit + bsrl b1238_fix //test for bug1238 case + moveml USER_DA(%a6),%d0/%d1 + bras inex_done +inex_cke1: + bclrb #E1,E_BYTE(%a6) +inex_done: + frestore (%sp)+ + unlk %a6 + jmp ([SYM(M68040FPSPUserExceptionHandlers)+2*4],za0) + +// +// Overflow exception +// + .global SYM(_fpspEntry_ovfl) + .global real_ovfl +SYM(_fpspEntry_ovfl): + jmp fpsp_ovfl +real_ovfl: + link %a6,#-LOCAL_SIZE + fsave -(%sp) + bclrb #E3,E_BYTE(%a6) //clear and test E3 flag + bnes ovfl_done + bclrb #E1,E_BYTE(%a6) +ovfl_done: + frestore (%sp)+ + unlk %a6 + jmp ([SYM(M68040FPSPUserExceptionHandlers)+6*4],za0) + +// +// Underflow exception +// + .global SYM(_fpspEntry_unfl) + .global real_unfl +SYM(_fpspEntry_unfl): + jmp fpsp_unfl +real_unfl: + link %a6,#-LOCAL_SIZE + fsave -(%sp) + bclrb #E3,E_BYTE(%a6) //clear and test E3 flag + bnes unfl_done + bclrb #E1,E_BYTE(%a6) +unfl_done: + frestore (%sp)+ + unlk %a6 + jmp ([SYM(M68040FPSPUserExceptionHandlers)+4*4],za0) + +// +// Signalling NAN exception +// + .global SYM(_fpspEntry_snan) + .global real_snan +SYM(_fpspEntry_snan): +snan: + jmp fpsp_snan +real_snan: + link %a6,#-LOCAL_SIZE + fsave -(%sp) + bclrb #E1,E_BYTE(%a6) //snan is always an E1 exception + frestore (%sp)+ + unlk %a6 + jmp ([SYM(M68040FPSPUserExceptionHandlers)+7*4],za0) + +// +// Operand Error exception +// + .global SYM(_fpspEntry_operr) + .global real_operr +SYM(_fpspEntry_operr): + jmp fpsp_operr +real_operr: + link %a6,#-LOCAL_SIZE + fsave -(%sp) + bclrb #E1,E_BYTE(%a6) //operr is always an E1 exception + frestore (%sp)+ + unlk %a6 + jmp ([SYM(M68040FPSPUserExceptionHandlers)+5*4],za0) + +// +// BSUN exception +// +// This sample handler simply clears the nan bit in the FPSR. +// + .global SYM(_fpspEntry_bsun) + .global real_bsun +SYM(_fpspEntry_bsun): + jmp fpsp_bsun +real_bsun: + link %a6,#-LOCAL_SIZE + fsave -(%sp) + bclrb #E1,E_BYTE(%a6) //bsun is always an E1 exception + fmovel %FPSR,-(%sp) + bclrb #nan_bit,(%sp) + fmovel (%sp)+,%FPSR + frestore (%sp)+ + unlk %a6 + jmp ([SYM(M68040FPSPUserExceptionHandlers)+1*4],za0) + +// +// F-line exception +// +// A 'real' F-line exception is one that the FPSP is not supposed to +// handle. E.g. an instruction with a co-processor ID that is not 1. +// + .global SYM(_fpspEntry_fline) + .global real_fline +SYM(_fpspEntry_fline): + jmp fpsp_fline +real_fline: + jmp ([SYM(M68040FPSPUserExceptionHandlers)+0*4],za0) + +// +// Unsupported data type exception +// + .global SYM(_fpspEntry_unsupp) + .global real_unsupp +SYM(_fpspEntry_unsupp): + jmp fpsp_unsupp +real_unsupp: + link %a6,#-LOCAL_SIZE + fsave -(%sp) + bclrb #E1,E_BYTE(%a6) //unsupp is always an E1 exception + frestore (%sp)+ + unlk %a6 + jmp ([SYM(M68040FPSPUserExceptionHandlers)+8*4],za0) + +// +// Trace exception +// + .global real_trace +real_trace: + trap #10 + +// +// fpsp_fmt_error --- exit point for frame format error +// +// The fpu stack frame does not match the frames existing +// or planned at the time of this writing. The fpsp is +// unable to handle frame sizes not in the following +// version:size pairs: +// +// {4060, 4160} - busy frame +// {4028, 4130} - unimp frame +// {4000, 4100} - idle frame +// + .global fpsp_fmt_error +fpsp_fmt_error: + trap #11 + +// +// fpsp_done --- FPSP exit point +// +// The exception has been handled by the package and we are ready +// to return to user mode, but there may be OS specific code +// to execute before we do. If there is, do it now. +// +// For now, the RTEMS does not bother looking at the +// possibility that it is time to reschedule.... +// + + .global fpsp_done +fpsp_done: + rte + +// +// mem_write --- write to user or supervisor address space +// +// Writes to memory while in supervisor mode. +// +// a0 - supervisor source address +// a1 - user/supervisor destination address +// d0 - number of bytes to write (maximum count is 12) +// + .global mem_write +mem_write: + btstb #5,EXC_SR(%a6) //check for supervisor state + beqs user_write +super_write: + moveb (%a0)+,(%a1)+ + subql #1,%d0 + bnes super_write + rts +user_write: + movel %d1,-(%sp) //preserve d1 just in case + movel %d0,-(%sp) + movel %a1,-(%sp) + movel %a0,-(%sp) + jsr copyout + addw #12,%sp + movel (%sp)+,%d1 + rts +// +// mem_read --- read from user or supervisor address space +// +// Reads from memory while in supervisor mode. +// +// The FPSP calls mem_read to read the original F-line instruction in order +// to extract the data register number when the 'Dn' addressing mode is +// used. +// +//Input: +// a0 - user/supervisor source address +// a1 - supervisor destination address +// d0 - number of bytes to read (maximum count is 12) +// +// Like mem_write, mem_read always reads with a supervisor +// destination address on the supervisor stack. Also like mem_write, +// the EXC_SR is checked and a simple memory copy is done if reading +// from supervisor space is indicated. +// + .global mem_read +mem_read: + btstb #5,EXC_SR(%a6) //check for supervisor state + beqs user_read +super_read: + moveb (%a0)+,(%a1)+ + subql #1,%d0 + bnes super_read + rts +user_read: + movel %d1,-(%sp) //preserve d1 just in case + movel %d0,-(%sp) + movel %a1,-(%sp) + movel %a0,-(%sp) + jsr copyin + addw #12,%sp + movel (%sp)+,%d1 + rts + +// +// Use these routines if your kernel does not have copyout/copyin equivalents. +// Assumes that D0/D1/A0/A1 are scratch registers. copyout overwrites DFC, +// and copyin overwrites SFC. +// +copyout: + movel 4(%sp),%a0 // source + movel 8(%sp),%a1 // destination + movel 12(%sp),%d0 // count + subl #1,%d0 // dec count by 1 for dbra + movel #1,%d1 + movec %d1,%DFC // set dfc for user data space +moreout: + moveb (%a0)+,%d1 // fetch supervisor byte + movesb %d1,(%a1)+ // write user byte + dbf %d0,moreout + rts + +copyin: + movel 4(%sp),%a0 // source + movel 8(%sp),%a1 // destination + movel 12(%sp),%d0 // count + subl #1,%d0 // dec count by 1 for dbra + movel #1,%d1 + movec %d1,%SFC // set sfc for user space +morein: + movesb (%a0)+,%d1 // fetch user byte + moveb %d1,(%a1)+ // write supervisor byte + dbf %d0,morein + rts + + |end |