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516 lines
12 KiB
516 lines
12 KiB
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| skeleton.sa 3.2 4/26/91
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| This file contains code that is system dependent and will
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| need to be modified to install the FPSP.
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| Each entry point for exception 'xxxx' begins with a 'jmp fpsp_xxxx'.
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| Put any target system specific handling that must be done immediately
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| before the jump instruction. If there no handling necessary, then
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| the 'fpsp_xxxx' handler entry point should be placed in the exception
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| table so that the 'jmp' can be eliminated. If the FPSP determines that the
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| exception is one that must be reported then there will be a
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| return from the package by a 'jmp real_xxxx'. At that point
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| the machine state will be identical to the state before
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| the FPSP was entered. In particular, whatever condition
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| that caused the exception will still be pending when the FPSP
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| package returns. Thus, there will be system specific code
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| to handle the exception.
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| If the exception was completely handled by the package, then
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| the return will be via a 'jmp fpsp_done'. Unless there is
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| OS specific work to be done (such as handling a context switch or
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| interrupt) the user program can be resumed via 'rte'.
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| In the following skeleton code, some typical 'real_xxxx' handling
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| code is shown. This code may need to be moved to an appropriate
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| place in the target system, or rewritten.
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| Copyright (C) Motorola, Inc. 1990
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| All Rights Reserved
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| THIS IS UNPUBLISHED PROPRIETARY SOURCE CODE OF MOTOROLA
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| The copyright notice above does not evidence any
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| actual or intended publication of such source code.
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| Modified for Linux-1.3.x by Jes Sorensen (jds@kom.auc.dk)
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#include <linux/linkage.h>
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#include <asm/entry.h>
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#include <asm/offsets.h>
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|SKELETON idnt 2,1 | Motorola 040 Floating Point Software Package
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|section 15
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| The following counters are used for standalone testing
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|section 8
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#include "fpsp.h"
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|xref b1238_fix
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| Divide by Zero exception
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| All dz exceptions are 'real', hence no fpsp_dz entry point.
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.global dz
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.global real_dz
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dz:
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real_dz:
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link %a6,#-LOCAL_SIZE
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fsave -(%sp)
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bclrb #E1,E_BYTE(%a6)
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frestore (%sp)+
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unlk %a6
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SAVE_ALL_INT
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GET_CURRENT(%d0)
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movel %sp,%sp@- | stack frame pointer argument
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bsrl trap_c
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addql #4,%sp
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bral ret_from_exception
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| Inexact exception
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| All inexact exceptions are real, but the 'real' handler
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| will probably want to clear the pending exception.
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| The provided code will clear the E3 exception (if pending),
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| otherwise clear the E1 exception. The frestore is not really
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| necessary for E1 exceptions.
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| Code following the 'inex' label is to handle bug #1232. In this
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| bug, if an E1 snan, ovfl, or unfl occurred, and the process was
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| swapped out before taking the exception, the exception taken on
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| return was inex, rather than the correct exception. The snan, ovfl,
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| and unfl exception to be taken must not have been enabled. The
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| fix is to check for E1, and the existence of one of snan, ovfl,
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| or unfl bits set in the fpsr. If any of these are set, branch
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| to the appropriate handler for the exception in the fpsr. Note
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| that this fix is only for d43b parts, and is skipped if the
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| version number is not $40.
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.global real_inex
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.global inex
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inex:
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link %a6,#-LOCAL_SIZE
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fsave -(%sp)
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cmpib #VER_40,(%sp) |test version number
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bnes not_fmt40
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fmovel %fpsr,-(%sp)
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btstb #E1,E_BYTE(%a6) |test for E1 set
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beqs not_b1232
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btstb #snan_bit,2(%sp) |test for snan
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beq inex_ckofl
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addl #4,%sp
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frestore (%sp)+
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unlk %a6
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bra snan
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inex_ckofl:
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btstb #ovfl_bit,2(%sp) |test for ovfl
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beq inex_ckufl
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addl #4,%sp
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frestore (%sp)+
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unlk %a6
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bra ovfl
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inex_ckufl:
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btstb #unfl_bit,2(%sp) |test for unfl
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beq not_b1232
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addl #4,%sp
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frestore (%sp)+
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unlk %a6
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bra unfl
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| We do not have the bug 1232 case. Clean up the stack and call
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| real_inex.
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not_b1232:
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addl #4,%sp
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frestore (%sp)+
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unlk %a6
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real_inex:
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link %a6,#-LOCAL_SIZE
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fsave -(%sp)
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not_fmt40:
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bclrb #E3,E_BYTE(%a6) |clear and test E3 flag
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beqs inex_cke1
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| Clear dirty bit on dest resister in the frame before branching
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| to b1238_fix.
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moveml %d0/%d1,USER_DA(%a6)
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bfextu CMDREG1B(%a6){#6:#3},%d0 |get dest reg no
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bclrb %d0,FPR_DIRTY_BITS(%a6) |clr dest dirty bit
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bsrl b1238_fix |test for bug1238 case
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moveml USER_DA(%a6),%d0/%d1
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bras inex_done
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inex_cke1:
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bclrb #E1,E_BYTE(%a6)
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inex_done:
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frestore (%sp)+
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unlk %a6
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SAVE_ALL_INT
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GET_CURRENT(%d0)
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movel %sp,%sp@- | stack frame pointer argument
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bsrl trap_c
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addql #4,%sp
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bral ret_from_exception
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| Overflow exception
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|xref fpsp_ovfl
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.global real_ovfl
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.global ovfl
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ovfl:
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jmp fpsp_ovfl
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real_ovfl:
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link %a6,#-LOCAL_SIZE
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fsave -(%sp)
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bclrb #E3,E_BYTE(%a6) |clear and test E3 flag
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bnes ovfl_done
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bclrb #E1,E_BYTE(%a6)
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ovfl_done:
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frestore (%sp)+
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unlk %a6
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SAVE_ALL_INT
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GET_CURRENT(%d0)
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movel %sp,%sp@- | stack frame pointer argument
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bsrl trap_c
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addql #4,%sp
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bral ret_from_exception
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| Underflow exception
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|xref fpsp_unfl
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.global real_unfl
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.global unfl
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unfl:
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jmp fpsp_unfl
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real_unfl:
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link %a6,#-LOCAL_SIZE
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fsave -(%sp)
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bclrb #E3,E_BYTE(%a6) |clear and test E3 flag
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bnes unfl_done
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bclrb #E1,E_BYTE(%a6)
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unfl_done:
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frestore (%sp)+
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unlk %a6
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SAVE_ALL_INT
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GET_CURRENT(%d0)
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movel %sp,%sp@- | stack frame pointer argument
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bsrl trap_c
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addql #4,%sp
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bral ret_from_exception
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| Signalling NAN exception
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|xref fpsp_snan
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.global real_snan
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.global snan
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snan:
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jmp fpsp_snan
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real_snan:
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link %a6,#-LOCAL_SIZE
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fsave -(%sp)
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bclrb #E1,E_BYTE(%a6) |snan is always an E1 exception
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frestore (%sp)+
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unlk %a6
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SAVE_ALL_INT
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GET_CURRENT(%d0)
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movel %sp,%sp@- | stack frame pointer argument
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bsrl trap_c
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addql #4,%sp
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bral ret_from_exception
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| Operand Error exception
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|xref fpsp_operr
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.global real_operr
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.global operr
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operr:
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jmp fpsp_operr
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real_operr:
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link %a6,#-LOCAL_SIZE
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fsave -(%sp)
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bclrb #E1,E_BYTE(%a6) |operr is always an E1 exception
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frestore (%sp)+
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unlk %a6
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SAVE_ALL_INT
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GET_CURRENT(%d0)
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movel %sp,%sp@- | stack frame pointer argument
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bsrl trap_c
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addql #4,%sp
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bral ret_from_exception
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| BSUN exception
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| This sample handler simply clears the nan bit in the FPSR.
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|xref fpsp_bsun
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.global real_bsun
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.global bsun
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bsun:
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jmp fpsp_bsun
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real_bsun:
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link %a6,#-LOCAL_SIZE
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fsave -(%sp)
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bclrb #E1,E_BYTE(%a6) |bsun is always an E1 exception
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fmovel %FPSR,-(%sp)
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bclrb #nan_bit,(%sp)
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fmovel (%sp)+,%FPSR
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frestore (%sp)+
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unlk %a6
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SAVE_ALL_INT
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GET_CURRENT(%d0)
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movel %sp,%sp@- | stack frame pointer argument
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bsrl trap_c
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addql #4,%sp
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bral ret_from_exception
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| F-line exception
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| A 'real' F-line exception is one that the FPSP isn't supposed to
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| handle. E.g. an instruction with a co-processor ID that is not 1.
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|xref fpsp_fline
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.global real_fline
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.global fline
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fline:
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jmp fpsp_fline
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real_fline:
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SAVE_ALL_INT
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GET_CURRENT(%d0)
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movel %sp,%sp@- | stack frame pointer argument
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bsrl trap_c
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addql #4,%sp
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bral ret_from_exception
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| Unsupported data type exception
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|xref fpsp_unsupp
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.global real_unsupp
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.global unsupp
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unsupp:
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jmp fpsp_unsupp
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real_unsupp:
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link %a6,#-LOCAL_SIZE
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fsave -(%sp)
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bclrb #E1,E_BYTE(%a6) |unsupp is always an E1 exception
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frestore (%sp)+
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unlk %a6
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SAVE_ALL_INT
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GET_CURRENT(%d0)
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movel %sp,%sp@- | stack frame pointer argument
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bsrl trap_c
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addql #4,%sp
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bral ret_from_exception
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| Trace exception
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.global real_trace
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real_trace:
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bral trap
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| fpsp_fmt_error --- exit point for frame format error
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| The fpu stack frame does not match the frames existing
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| or planned at the time of this writing. The fpsp is
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| unable to handle frame sizes not in the following
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| version:size pairs:
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| {4060, 4160} - busy frame
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| {4028, 4130} - unimp frame
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| {4000, 4100} - idle frame
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| This entry point simply holds an f-line illegal value.
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| Replace this with a call to your kernel panic code or
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| code to handle future revisions of the fpu.
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.global fpsp_fmt_error
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fpsp_fmt_error:
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.long 0xf27f0000 |f-line illegal
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| fpsp_done --- FPSP exit point
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| The exception has been handled by the package and we are ready
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| to return to user mode, but there may be OS specific code
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| to execute before we do. If there is, do it now.
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.global fpsp_done
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fpsp_done:
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btst #0x5,%sp@ | supervisor bit set in saved SR?
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beq .Lnotkern
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rte
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.Lnotkern:
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SAVE_ALL_INT
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GET_CURRENT(%d0)
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tstb %curptr@(TASK_NEEDRESCHED)
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jne ret_from_exception | deliver signals,
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| reschedule etc..
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RESTORE_ALL
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| mem_write --- write to user or supervisor address space
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| Writes to memory while in supervisor mode. copyout accomplishes
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| this via a 'moves' instruction. copyout is a UNIX SVR3 (and later) function.
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| If you don't have copyout, use the local copy of the function below.
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| a0 - supervisor source address
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| a1 - user destination address
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| d0 - number of bytes to write (maximum count is 12)
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| The supervisor source address is guaranteed to point into the supervisor
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| stack. The result is that a UNIX
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| process is allowed to sleep as a consequence of a page fault during
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| copyout. The probability of a page fault is exceedingly small because
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| the 68040 always reads the destination address and thus the page
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| faults should have already been handled.
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| If the EXC_SR shows that the exception was from supervisor space,
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| then just do a dumb (and slow) memory move. In a UNIX environment
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| there shouldn't be any supervisor mode floating point exceptions.
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.global mem_write
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mem_write:
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btstb #5,EXC_SR(%a6) |check for supervisor state
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beqs user_write
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super_write:
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moveb (%a0)+,(%a1)+
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subql #1,%d0
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bnes super_write
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rts
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user_write:
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movel %d1,-(%sp) |preserve d1 just in case
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movel %d0,-(%sp)
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movel %a1,-(%sp)
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movel %a0,-(%sp)
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jsr copyout
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addw #12,%sp
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movel (%sp)+,%d1
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rts
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| mem_read --- read from user or supervisor address space
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| Reads from memory while in supervisor mode. copyin accomplishes
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| this via a 'moves' instruction. copyin is a UNIX SVR3 (and later) function.
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| If you don't have copyin, use the local copy of the function below.
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| The FPSP calls mem_read to read the original F-line instruction in order
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| to extract the data register number when the 'Dn' addressing mode is
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| used.
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|Input:
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| a0 - user source address
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| a1 - supervisor destination address
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| d0 - number of bytes to read (maximum count is 12)
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| Like mem_write, mem_read always reads with a supervisor
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| destination address on the supervisor stack. Also like mem_write,
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| the EXC_SR is checked and a simple memory copy is done if reading
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| from supervisor space is indicated.
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.global mem_read
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mem_read:
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btstb #5,EXC_SR(%a6) |check for supervisor state
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beqs user_read
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super_read:
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moveb (%a0)+,(%a1)+
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subql #1,%d0
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bnes super_read
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rts
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user_read:
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movel %d1,-(%sp) |preserve d1 just in case
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movel %d0,-(%sp)
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movel %a1,-(%sp)
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movel %a0,-(%sp)
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jsr copyin
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addw #12,%sp
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movel (%sp)+,%d1
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rts
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| Use these routines if your kernel doesn't have copyout/copyin equivalents.
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| Assumes that D0/D1/A0/A1 are scratch registers. copyout overwrites DFC,
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| and copyin overwrites SFC.
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copyout:
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movel 4(%sp),%a0 | source
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movel 8(%sp),%a1 | destination
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movel 12(%sp),%d0 | count
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subl #1,%d0 | dec count by 1 for dbra
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movel #1,%d1
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| DFC is already set
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| movec %d1,%DFC | set dfc for user data space
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moreout:
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moveb (%a0)+,%d1 | fetch supervisor byte
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out_ea:
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movesb %d1,(%a1)+ | write user byte
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dbf %d0,moreout
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rts
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copyin:
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movel 4(%sp),%a0 | source
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movel 8(%sp),%a1 | destination
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movel 12(%sp),%d0 | count
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subl #1,%d0 | dec count by 1 for dbra
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movel #1,%d1
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| SFC is already set
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| movec %d1,%SFC | set sfc for user space
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morein:
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in_ea:
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movesb (%a0)+,%d1 | fetch user byte
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moveb %d1,(%a1)+ | write supervisor byte
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dbf %d0,morein
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rts
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.section .fixup,#alloc,#execinstr
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.even
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1:
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jbra fpsp040_die
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.section __ex_table,#alloc
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.align 4
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.long in_ea,1b
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.long out_ea,1b
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|end
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