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Diffstat (limited to 'arch/m68k/fpsp040/skeleton.S')
| -rw-r--r-- | arch/m68k/fpsp040/skeleton.S | 516 |
1 files changed, 516 insertions, 0 deletions
diff --git a/arch/m68k/fpsp040/skeleton.S b/arch/m68k/fpsp040/skeleton.S new file mode 100644 index 0000000..dbc1255 --- /dev/null +++ b/arch/m68k/fpsp040/skeleton.S @@ -0,0 +1,516 @@ +| +| 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 +| + +| Copyright (C) Motorola, Inc. 1990 +| All Rights Reserved +| +| THIS IS UNPUBLISHED PROPRIETARY SOURCE CODE OF MOTOROLA +| The copyright notice above does not evidence any +| actual or intended publication of such source code. + +| +| Modified for Linux-1.3.x by Jes Sorensen (jds@kom.auc.dk) +| + +#include <linux/linkage.h> +#include <asm/entry.h> +#include <asm/offsets.h> + +|SKELETON idnt 2,1 | Motorola 040 Floating Point Software Package + + |section 15 +| +| The following counters are used for standalone testing +| + + |section 8 + +#include "fpsp.h" + + |xref b1238_fix + +| +| Divide by Zero exception +| +| All dz exceptions are 'real', hence no fpsp_dz entry point. +| + .global dz + .global real_dz +dz: +real_dz: + link %a6,#-LOCAL_SIZE + fsave -(%sp) + bclrb #E1,E_BYTE(%a6) + frestore (%sp)+ + unlk %a6 + + SAVE_ALL_INT + GET_CURRENT(%d0) + movel %sp,%sp@- | stack frame pointer argument + bsrl trap_c + addql #4,%sp + bral ret_from_exception + +| +| 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 real_inex + .global inex +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 ovfl +inex_ckufl: + btstb #unfl_bit,2(%sp) |test for unfl + beq not_b1232 + addl #4,%sp + frestore (%sp)+ + unlk %a6 + bra 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 + + SAVE_ALL_INT + GET_CURRENT(%d0) + movel %sp,%sp@- | stack frame pointer argument + bsrl trap_c + addql #4,%sp + bral ret_from_exception + +| +| Overflow exception +| + |xref fpsp_ovfl + .global real_ovfl + .global ovfl +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 + + SAVE_ALL_INT + GET_CURRENT(%d0) + movel %sp,%sp@- | stack frame pointer argument + bsrl trap_c + addql #4,%sp + bral ret_from_exception + +| +| Underflow exception +| + |xref fpsp_unfl + .global real_unfl + .global unfl +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 + + SAVE_ALL_INT + GET_CURRENT(%d0) + movel %sp,%sp@- | stack frame pointer argument + bsrl trap_c + addql #4,%sp + bral ret_from_exception + +| +| Signalling NAN exception +| + |xref fpsp_snan + .global real_snan + .global 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 + + SAVE_ALL_INT + GET_CURRENT(%d0) + movel %sp,%sp@- | stack frame pointer argument + bsrl trap_c + addql #4,%sp + bral ret_from_exception + +| +| Operand Error exception +| + |xref fpsp_operr + .global real_operr + .global operr +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 + + SAVE_ALL_INT + GET_CURRENT(%d0) + movel %sp,%sp@- | stack frame pointer argument + bsrl trap_c + addql #4,%sp + bral ret_from_exception + + +| +| BSUN exception +| +| This sample handler simply clears the nan bit in the FPSR. +| + |xref fpsp_bsun + .global real_bsun + .global bsun +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 + + SAVE_ALL_INT + GET_CURRENT(%d0) + movel %sp,%sp@- | stack frame pointer argument + bsrl trap_c + addql #4,%sp + bral ret_from_exception + +| +| F-line exception +| +| A 'real' F-line exception is one that the FPSP isn't supposed to +| handle. E.g. an instruction with a co-processor ID that is not 1. +| +| + |xref fpsp_fline + .global real_fline + .global fline +fline: + jmp fpsp_fline +real_fline: + + SAVE_ALL_INT + GET_CURRENT(%d0) + movel %sp,%sp@- | stack frame pointer argument + bsrl trap_c + addql #4,%sp + bral ret_from_exception + +| +| Unsupported data type exception +| + |xref fpsp_unsupp + .global real_unsupp + .global unsupp +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 + + SAVE_ALL_INT + GET_CURRENT(%d0) + movel %sp,%sp@- | stack frame pointer argument + bsrl trap_c + addql #4,%sp + bral ret_from_exception + +| +| Trace exception +| + .global real_trace +real_trace: + | + bral trap + +| +| 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 +| +| This entry point simply holds an f-line illegal value. +| Replace this with a call to your kernel panic code or +| code to handle future revisions of the fpu. +| + .global fpsp_fmt_error +fpsp_fmt_error: + + .long 0xf27f0000 |f-line illegal + +| +| 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. +| +| + + .global fpsp_done +fpsp_done: + btst #0x5,%sp@ | supervisor bit set in saved SR? + beq .Lnotkern + rte +.Lnotkern: + SAVE_ALL_INT + GET_CURRENT(%d0) + tstb %curptr@(TASK_NEEDRESCHED) + jne ret_from_exception | deliver signals, + | reschedule etc.. + RESTORE_ALL + +| +| mem_write --- write to user or supervisor address space +| +| Writes to memory while in supervisor mode. copyout accomplishes +| this via a 'moves' instruction. copyout is a UNIX SVR3 (and later) function. +| If you don't have copyout, use the local copy of the function below. +| +| a0 - supervisor source address +| a1 - user destination address +| d0 - number of bytes to write (maximum count is 12) +| +| The supervisor source address is guaranteed to point into the supervisor +| stack. The result is that a UNIX +| process is allowed to sleep as a consequence of a page fault during +| copyout. The probability of a page fault is exceedingly small because +| the 68040 always reads the destination address and thus the page +| faults should have already been handled. +| +| If the EXC_SR shows that the exception was from supervisor space, +| then just do a dumb (and slow) memory move. In a UNIX environment +| there shouldn't be any supervisor mode floating point exceptions. +| + .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. copyin accomplishes +| this via a 'moves' instruction. copyin is a UNIX SVR3 (and later) function. +| If you don't have copyin, use the local copy of the function below. +| +| 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 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 doesn't 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 + +| DFC is already set +| movec %d1,%DFC | set dfc for user data space +moreout: + moveb (%a0)+,%d1 | fetch supervisor byte +out_ea: + 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 +| SFC is already set +| movec %d1,%SFC | set sfc for user space +morein: +in_ea: + movesb (%a0)+,%d1 | fetch user byte + moveb %d1,(%a1)+ | write supervisor byte + dbf %d0,morein + rts + + .section .fixup,#alloc,#execinstr + .even +1: + jbra fpsp040_die + + .section __ex_table,#alloc + .align 4 + + .long in_ea,1b + .long out_ea,1b + + |end |