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+|
+| gen_except.sa 3.7 1/16/92
+|
+| gen_except --- FPSP routine to detect reportable exceptions
+|
+| This routine compares the exception enable byte of the
+| user_fpcr on the stack with the exception status byte
+| of the user_fpsr.
+|
+| Any routine which may report an exceptions must load
+| the stack frame in memory with the exceptional operand(s).
+|
+| Priority for exceptions is:
+|
+| Highest: bsun
+| snan
+| operr
+| ovfl
+| unfl
+| dz
+| inex2
+| Lowest: inex1
+|
+| Note: The IEEE standard specifies that inex2 is to be
+| reported if ovfl occurs and the ovfl enable bit is not
+| set but the inex2 enable bit is.
+|
+|
+| 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+| THIS IS UNPUBLISHED PROPRIETARY SOURCE CODE OF MOTOROLA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.
+
+GEN_EXCEPT: |idnt 2,1 | Motorola 040 Floating Point Software Package
+
+ |section 8
+
+#include "fpsp.h"
+
+ |xref real_trace
+ |xref fpsp_done
+ |xref fpsp_fmt_error
+
+exc_tbl:
+ .long bsun_exc
+ .long commonE1
+ .long commonE1
+ .long ovfl_unfl
+ .long ovfl_unfl
+ .long commonE1
+ .long commonE3
+ .long commonE3
+ .long no_match
+
+ .global gen_except
+gen_except:
+ cmpib #IDLE_SIZE-4,1(%a7) |test for idle frame
+ beq do_check |go handle idle frame
+ cmpib #UNIMP_40_SIZE-4,1(%a7) |test for orig unimp frame
+ beqs unimp_x |go handle unimp frame
+ cmpib #UNIMP_41_SIZE-4,1(%a7) |test for rev unimp frame
+ beqs unimp_x |go handle unimp frame
+ cmpib #BUSY_SIZE-4,1(%a7) |if size <> $60, fmt error
+ bnel fpsp_fmt_error
+ leal BUSY_SIZE+LOCAL_SIZE(%a7),%a1 |init a1 so fpsp.h
+| ;equates will work
+| Fix up the new busy frame with entries from the unimp frame
+|
+ movel ETEMP_EX(%a6),ETEMP_EX(%a1) |copy etemp from unimp
+ movel ETEMP_HI(%a6),ETEMP_HI(%a1) |frame to busy frame
+ movel ETEMP_LO(%a6),ETEMP_LO(%a1)
+ movel CMDREG1B(%a6),CMDREG1B(%a1) |set inst in frame to unimp
+ movel CMDREG1B(%a6),%d0 |fix cmd1b to make it
+ andl #0x03c30000,%d0 |work for cmd3b
+ bfextu CMDREG1B(%a6){#13:#1},%d1 |extract bit 2
+ lsll #5,%d1
+ swap %d1
+ orl %d1,%d0 |put it in the right place
+ bfextu CMDREG1B(%a6){#10:#3},%d1 |extract bit 3,4,5
+ lsll #2,%d1
+ swap %d1
+ orl %d1,%d0 |put them in the right place
+ movel %d0,CMDREG3B(%a1) |in the busy frame
+|
+| Or in the FPSR from the emulation with the USER_FPSR on the stack.
+|
+ fmovel %FPSR,%d0
+ orl %d0,USER_FPSR(%a6)
+ movel USER_FPSR(%a6),FPSR_SHADOW(%a1) |set exc bits
+ orl #sx_mask,E_BYTE(%a1)
+ bra do_clean
+
+|
+| Frame is an unimp frame possible resulting from an fmove <ea>,fp0
+| that caused an exception
+|
+| a1 is modified to point into the new frame allowing fpsp equates
+| to be valid.
+|
+unimp_x:
+ cmpib #UNIMP_40_SIZE-4,1(%a7) |test for orig unimp frame
+ bnes test_rev
+ leal UNIMP_40_SIZE+LOCAL_SIZE(%a7),%a1
+ bras unimp_con
+test_rev:
+ cmpib #UNIMP_41_SIZE-4,1(%a7) |test for rev unimp frame
+ bnel fpsp_fmt_error |if not $28 or $30
+ leal UNIMP_41_SIZE+LOCAL_SIZE(%a7),%a1
+
+unimp_con:
+|
+| Fix up the new unimp frame with entries from the old unimp frame
+|
+ movel CMDREG1B(%a6),CMDREG1B(%a1) |set inst in frame to unimp
+|
+| Or in the FPSR from the emulation with the USER_FPSR on the stack.
+|
+ fmovel %FPSR,%d0
+ orl %d0,USER_FPSR(%a6)
+ bra do_clean
+
+|
+| Frame is idle, so check for exceptions reported through
+| USER_FPSR and set the unimp frame accordingly.
+| A7 must be incremented to the point before the
+| idle fsave vector to the unimp vector.
+|
+
+do_check:
+ addl #4,%a7 |point A7 back to unimp frame
+|
+| Or in the FPSR from the emulation with the USER_FPSR on the stack.
+|
+ fmovel %FPSR,%d0
+ orl %d0,USER_FPSR(%a6)
+|
+| On a busy frame, we must clear the nmnexc bits.
+|
+ cmpib #BUSY_SIZE-4,1(%a7) |check frame type
+ bnes check_fr |if busy, clr nmnexc
+ clrw NMNEXC(%a6) |clr nmnexc & nmcexc
+ btstb #5,CMDREG1B(%a6) |test for fmove out
+ bnes frame_com
+ movel USER_FPSR(%a6),FPSR_SHADOW(%a6) |set exc bits
+ orl #sx_mask,E_BYTE(%a6)
+ bras frame_com
+check_fr:
+ cmpb #UNIMP_40_SIZE-4,1(%a7)
+ beqs frame_com
+ clrw NMNEXC(%a6)
+frame_com:
+ moveb FPCR_ENABLE(%a6),%d0 |get fpcr enable byte
+ andb FPSR_EXCEPT(%a6),%d0 |and in the fpsr exc byte
+ bfffo %d0{#24:#8},%d1 |test for first set bit
+ leal exc_tbl,%a0 |load jmp table address
+ subib #24,%d1 |normalize bit offset to 0-8
+ movel (%a0,%d1.w*4),%a0 |load routine address based
+| ;based on first enabled exc
+ jmp (%a0) |jump to routine
+|
+| Bsun is not possible in unimp or unsupp
+|
+bsun_exc:
+ bra do_clean
+|
+| The typical work to be done to the unimp frame to report an
+| exception is to set the E1/E3 byte and clr the U flag.
+| commonE1 does this for E1 exceptions, which are snan,
+| operr, and dz. commonE3 does this for E3 exceptions, which
+| are inex2 and inex1, and also clears the E1 exception bit
+| left over from the unimp exception.
+|
+commonE1:
+ bsetb #E1,E_BYTE(%a6) |set E1 flag
+ bra commonE |go clean and exit
+
+commonE3:
+ tstb UFLG_TMP(%a6) |test flag for unsup/unimp state
+ bnes unsE3
+uniE3:
+ bsetb #E3,E_BYTE(%a6) |set E3 flag
+ bclrb #E1,E_BYTE(%a6) |clr E1 from unimp
+ bra commonE
+
+unsE3:
+ tstb RES_FLG(%a6)
+ bnes unsE3_0
+unsE3_1:
+ bsetb #E3,E_BYTE(%a6) |set E3 flag
+unsE3_0:
+ bclrb #E1,E_BYTE(%a6) |clr E1 flag
+ movel CMDREG1B(%a6),%d0
+ andl #0x03c30000,%d0 |work for cmd3b
+ bfextu CMDREG1B(%a6){#13:#1},%d1 |extract bit 2
+ lsll #5,%d1
+ swap %d1
+ orl %d1,%d0 |put it in the right place
+ bfextu CMDREG1B(%a6){#10:#3},%d1 |extract bit 3,4,5
+ lsll #2,%d1
+ swap %d1
+ orl %d1,%d0 |put them in the right place
+ movel %d0,CMDREG3B(%a6) |in the busy frame
+
+commonE:
+ bclrb #UFLAG,T_BYTE(%a6) |clr U flag from unimp
+ bra do_clean |go clean and exit
+|
+| No bits in the enable byte match existing exceptions. Check for
+| the case of the ovfl exc without the ovfl enabled, but with
+| inex2 enabled.
+|
+no_match:
+ btstb #inex2_bit,FPCR_ENABLE(%a6) |check for ovfl/inex2 case
+ beqs no_exc |if clear, exit
+ btstb #ovfl_bit,FPSR_EXCEPT(%a6) |now check ovfl
+ beqs no_exc |if clear, exit
+ bras ovfl_unfl |go to unfl_ovfl to determine if
+| ;it is an unsupp or unimp exc
+
+| No exceptions are to be reported. If the instruction was
+| unimplemented, no FPU restore is necessary. If it was
+| unsupported, we must perform the restore.
+no_exc:
+ tstb UFLG_TMP(%a6) |test flag for unsupp/unimp state
+ beqs uni_no_exc
+uns_no_exc:
+ tstb RES_FLG(%a6) |check if frestore is needed
+ bne do_clean |if clear, no frestore needed
+uni_no_exc:
+ moveml USER_DA(%a6),%d0-%d1/%a0-%a1
+ fmovemx USER_FP0(%a6),%fp0-%fp3
+ fmoveml USER_FPCR(%a6),%fpcr/%fpsr/%fpiar
+ unlk %a6
+ bra finish_up
+|
+| Unsupported Data Type Handler:
+| Ovfl:
+| An fmoveout that results in an overflow is reported this way.
+| Unfl:
+| An fmoveout that results in an underflow is reported this way.
+|
+| Unimplemented Instruction Handler:
+| Ovfl:
+| Only scosh, setox, ssinh, stwotox, and scale can set overflow in
+| this manner.
+| Unfl:
+| Stwotox, setox, and scale can set underflow in this manner.
+| Any of the other Library Routines such that f(x)=x in which
+| x is an extended denorm can report an underflow exception.
+| It is the responsibility of the exception-causing exception
+| to make sure that WBTEMP is correct.
+|
+| The exceptional operand is in FP_SCR1.
+|
+ovfl_unfl:
+ tstb UFLG_TMP(%a6) |test flag for unsupp/unimp state
+ beqs ofuf_con
+|
+| The caller was from an unsupported data type trap. Test if the
+| caller set CU_ONLY. If so, the exceptional operand is expected in
+| FPTEMP, rather than WBTEMP.
+|
+ tstb CU_ONLY(%a6) |test if inst is cu-only
+ beq unsE3
+| move.w #$fe,CU_SAVEPC(%a6)
+ clrb CU_SAVEPC(%a6)
+ bsetb #E1,E_BYTE(%a6) |set E1 exception flag
+ movew ETEMP_EX(%a6),FPTEMP_EX(%a6)
+ movel ETEMP_HI(%a6),FPTEMP_HI(%a6)
+ movel ETEMP_LO(%a6),FPTEMP_LO(%a6)
+ bsetb #fptemp15_bit,DTAG(%a6) |set fpte15
+ bclrb #UFLAG,T_BYTE(%a6) |clr U flag from unimp
+ bra do_clean |go clean and exit
+
+ofuf_con:
+ moveb (%a7),VER_TMP(%a6) |save version number
+ cmpib #BUSY_SIZE-4,1(%a7) |check for busy frame
+ beqs busy_fr |if unimp, grow to busy
+ cmpib #VER_40,(%a7) |test for orig unimp frame
+ bnes try_41 |if not, test for rev frame
+ moveql #13,%d0 |need to zero 14 lwords
+ bras ofuf_fin
+try_41:
+ cmpib #VER_41,(%a7) |test for rev unimp frame
+ bnel fpsp_fmt_error |if neither, exit with error
+ moveql #11,%d0 |need to zero 12 lwords
+
+ofuf_fin:
+ clrl (%a7)
+loop1:
+ clrl -(%a7) |clear and dec a7
+ dbra %d0,loop1
+ moveb VER_TMP(%a6),(%a7)
+ moveb #BUSY_SIZE-4,1(%a7) |write busy fmt word.
+busy_fr:
+ movel FP_SCR1(%a6),WBTEMP_EX(%a6) |write
+ movel FP_SCR1+4(%a6),WBTEMP_HI(%a6) |exceptional op to
+ movel FP_SCR1+8(%a6),WBTEMP_LO(%a6) |wbtemp
+ bsetb #E3,E_BYTE(%a6) |set E3 flag
+ bclrb #E1,E_BYTE(%a6) |make sure E1 is clear
+ bclrb #UFLAG,T_BYTE(%a6) |clr U flag
+ movel USER_FPSR(%a6),FPSR_SHADOW(%a6)
+ orl #sx_mask,E_BYTE(%a6)
+ movel CMDREG1B(%a6),%d0 |fix cmd1b to make it
+ andl #0x03c30000,%d0 |work for cmd3b
+ bfextu CMDREG1B(%a6){#13:#1},%d1 |extract bit 2
+ lsll #5,%d1
+ swap %d1
+ orl %d1,%d0 |put it in the right place
+ bfextu CMDREG1B(%a6){#10:#3},%d1 |extract bit 3,4,5
+ lsll #2,%d1
+ swap %d1
+ orl %d1,%d0 |put them in the right place
+ movel %d0,CMDREG3B(%a6) |in the busy frame
+
+|
+| Check if the frame to be restored is busy or unimp.
+|** NOTE *** Bug fix for errata (0d43b #3)
+| If the frame is unimp, we must create a busy frame to
+| fix the bug with the nmnexc bits in cases in which they
+| are set by a previous instruction and not cleared by
+| the save. The frame will be unimp only if the final
+| instruction in an emulation routine caused the exception
+| by doing an fmove <ea>,fp0. The exception operand, in
+| internal format, is in fptemp.
+|
+do_clean:
+ cmpib #UNIMP_40_SIZE-4,1(%a7)
+ bnes do_con
+ moveql #13,%d0 |in orig, need to zero 14 lwords
+ bras do_build
+do_con:
+ cmpib #UNIMP_41_SIZE-4,1(%a7)
+ bnes do_restore |frame must be busy
+ moveql #11,%d0 |in rev, need to zero 12 lwords
+
+do_build:
+ moveb (%a7),VER_TMP(%a6)
+ clrl (%a7)
+loop2:
+ clrl -(%a7) |clear and dec a7
+ dbra %d0,loop2
+|
+| Use a1 as pointer into new frame. a6 is not correct if an unimp or
+| busy frame was created as the result of an exception on the final
+| instruction of an emulation routine.
+|
+| We need to set the nmcexc bits if the exception is E1. Otherwise,
+| the exc taken will be inex2.
+|
+ leal BUSY_SIZE+LOCAL_SIZE(%a7),%a1 |init a1 for new frame
+ moveb VER_TMP(%a6),(%a7) |write busy fmt word
+ moveb #BUSY_SIZE-4,1(%a7)
+ movel FP_SCR1(%a6),WBTEMP_EX(%a1) |write
+ movel FP_SCR1+4(%a6),WBTEMP_HI(%a1) |exceptional op to
+ movel FP_SCR1+8(%a6),WBTEMP_LO(%a1) |wbtemp
+| btst.b #E1,E_BYTE(%a1)
+| beq.b do_restore
+ bfextu USER_FPSR(%a6){#17:#4},%d0 |get snan/operr/ovfl/unfl bits
+ bfins %d0,NMCEXC(%a1){#4:#4} |and insert them in nmcexc
+ movel USER_FPSR(%a6),FPSR_SHADOW(%a1) |set exc bits
+ orl #sx_mask,E_BYTE(%a1)
+
+do_restore:
+ moveml USER_DA(%a6),%d0-%d1/%a0-%a1
+ fmovemx USER_FP0(%a6),%fp0-%fp3
+ fmoveml USER_FPCR(%a6),%fpcr/%fpsr/%fpiar
+ frestore (%a7)+
+ tstb RES_FLG(%a6) |RES_FLG indicates a "continuation" frame
+ beq cont
+ bsr bug1384
+cont:
+ unlk %a6
+|
+| If trace mode enabled, then go to trace handler. This handler
+| cannot have any fp instructions. If there are fp inst's and an
+| exception has been restored into the machine then the exception
+| will occur upon execution of the fp inst. This is not desirable
+| in the kernel (supervisor mode). See MC68040 manual Section 9.3.8.
+|
+finish_up:
+ btstb #7,(%a7) |test T1 in SR
+ bnes g_trace
+ btstb #6,(%a7) |test T0 in SR
+ bnes g_trace
+ bral fpsp_done
+|
+| Change integer stack to look like trace stack
+| The address of the instruction that caused the
+| exception is already in the integer stack (is
+| the same as the saved friar)
+|
+| If the current frame is already a 6-word stack then all
+| that needs to be done is to change the vector# to TRACE.
+| If the frame is only a 4-word stack (meaning we got here
+| on an Unsupported data type exception), then we need to grow
+| the stack an extra 2 words and get the FPIAR from the FPU.
+|
+g_trace:
+ bftst EXC_VEC-4(%sp){#0:#4}
+ bne g_easy
+
+ subw #4,%sp | make room
+ movel 4(%sp),(%sp)
+ movel 8(%sp),4(%sp)
+ subw #BUSY_SIZE,%sp
+ fsave (%sp)
+ fmovel %fpiar,BUSY_SIZE+EXC_EA-4(%sp)
+ frestore (%sp)
+ addw #BUSY_SIZE,%sp
+
+g_easy:
+ movew #TRACE_VEC,EXC_VEC-4(%a7)
+ bral real_trace
+|
+| This is a work-around for hardware bug 1384.
+|
+bug1384:
+ link %a5,#0
+ fsave -(%sp)
+ cmpib #0x41,(%sp) | check for correct frame
+ beq frame_41
+ bgt nofix | if more advanced mask, do nada
+
+frame_40:
+ tstb 1(%sp) | check to see if idle
+ bne notidle
+idle40:
+ clrl (%sp) | get rid of old fsave frame
+ movel %d1,USER_D1(%a6) | save d1
+ movew #8,%d1 | place unimp frame instead
+loop40: clrl -(%sp)
+ dbra %d1,loop40
+ movel USER_D1(%a6),%d1 | restore d1
+ movel #0x40280000,-(%sp)
+ frestore (%sp)+
+ unlk %a5
+ rts
+
+frame_41:
+ tstb 1(%sp) | check to see if idle
+ bne notidle
+idle41:
+ clrl (%sp) | get rid of old fsave frame
+ movel %d1,USER_D1(%a6) | save d1
+ movew #10,%d1 | place unimp frame instead
+loop41: clrl -(%sp)
+ dbra %d1,loop41
+ movel USER_D1(%a6),%d1 | restore d1
+ movel #0x41300000,-(%sp)
+ frestore (%sp)+
+ unlk %a5
+ rts
+
+notidle:
+ bclrb #etemp15_bit,-40(%a5)
+ frestore (%sp)+
+ unlk %a5
+ rts
+
+nofix:
+ frestore (%sp)+
+ unlk %a5
+ rts
+
+ |end