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513 lines
12 KiB
513 lines
12 KiB
| |
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| skeleton.sa 3.2 4/26/91 |
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| |
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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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| |
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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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| |
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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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| |
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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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| |
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| Copyright (C) Motorola, Inc. 1990 |
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| All Rights Reserved |
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| |
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| For details on the license for this file, please see the |
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| file, README, in this same directory. |
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| |
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| Modified for Linux-1.3.x by Jes Sorensen (jds@kom.auc.dk) |
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| |
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#include <linux/linkage.h> |
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#include <asm/entry.h> |
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#include <asm/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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| |
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| The following counters are used for standalone testing |
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| |
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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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| |
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| All dz exceptions are 'real', hence no fpsp_dz entry point. |
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| |
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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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| |
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| Inexact exception |
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| |
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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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| |
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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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| |
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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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| |
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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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| |
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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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| |
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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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| |
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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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| |
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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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| |
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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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| |
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| F-line exception |
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| |
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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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| |
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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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| |
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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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| deliver signals, reschedule etc.. |
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jra ret_from_exception |
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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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| |
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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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| |
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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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