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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
|
| For details on the license for this file, please see the
| file, README, in this same directory.
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:
|