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|
|
| x_fline.sa 3.3 1/10/91
|
| fpsp_fline --- FPSP handler for fline exception
|
| First determine if the exception is one of the unimplemented
| floating point instructions. If so, let fpsp_unimp handle it.
| Next, determine if the instruction is an fmovecr with a non-zero
| <ea> field. If so, handle here and return. Otherwise, it
| must be a real F-line exception.
|
| 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.
X_FLINE: |idnt 2,1 | Motorola 040 Floating Point Software Package
|section 8
#include "fpsp.h"
|xref real_fline
|xref fpsp_unimp
|xref uni_2
|xref mem_read
|xref fpsp_fmt_error
.global fpsp_fline
fpsp_fline:
|
| check for unimplemented vector first. Use EXC_VEC-4 because
| the equate is valid only after a 'link a6' has pushed one more
| long onto the stack.
|
cmpw #UNIMP_VEC,EXC_VEC-4(%a7)
beql fpsp_unimp
|
| fmovecr with non-zero <ea> handling here
|
subl #4,%a7 |4 accounts for 2-word difference
| ;between six word frame (unimp) and
| ;four word frame
link %a6,#-LOCAL_SIZE
fsave -(%a7)
moveml %d0-%d1/%a0-%a1,USER_DA(%a6)
moveal EXC_PC+4(%a6),%a0 |get address of fline instruction
leal L_SCR1(%a6),%a1 |use L_SCR1 as scratch
movel #4,%d0
addl #4,%a6 |to offset the sub.l #4,a7 above so that
| ;a6 can point correctly to the stack frame
| ;before branching to mem_read
bsrl mem_read
subl #4,%a6
movel L_SCR1(%a6),%d0 |d0 contains the fline and command word
bfextu %d0{#4:#3},%d1 |extract coprocessor id
cmpib #1,%d1 |check if cpid=1
bne not_mvcr |exit if not
bfextu %d0{#16:#6},%d1
cmpib #0x17,%d1 |check if it is an FMOVECR encoding
bne not_mvcr
| ;if an FMOVECR instruction, fix stack
| ;and go to FPSP_UNIMP
fix_stack:
cmpib #VER_40,(%a7) |test for orig unimp frame
bnes ck_rev
subl #UNIMP_40_SIZE-4,%a7 |emulate an orig fsave
moveb #VER_40,(%a7)
moveb #UNIMP_40_SIZE-4,1(%a7)
clrw 2(%a7)
bras fix_con
ck_rev:
cmpib #VER_41,(%a7) |test for rev unimp frame
bnel fpsp_fmt_error |if not $40 or $41, exit with error
subl #UNIMP_41_SIZE-4,%a7 |emulate a rev fsave
moveb #VER_41,(%a7)
moveb #UNIMP_41_SIZE-4,1(%a7)
clrw 2(%a7)
fix_con:
movew EXC_SR+4(%a6),EXC_SR(%a6) |move stacked sr to new position
movel EXC_PC+4(%a6),EXC_PC(%a6) |move stacked pc to new position
fmovel EXC_PC(%a6),%FPIAR |point FPIAR to fline inst
movel #4,%d1
addl %d1,EXC_PC(%a6) |increment stacked pc value to next inst
movew #0x202c,EXC_VEC(%a6) |reformat vector to unimp
clrl EXC_EA(%a6) |clear the EXC_EA field
movew %d0,CMDREG1B(%a6) |move the lower word into CMDREG1B
clrl E_BYTE(%a6)
bsetb #UFLAG,T_BYTE(%a6)
moveml USER_DA(%a6),%d0-%d1/%a0-%a1 |restore data registers
bral uni_2
not_mvcr:
moveml USER_DA(%a6),%d0-%d1/%a0-%a1 |restore data registers
frestore (%a7)+
unlk %a6
addl #4,%a7
bral real_fline
|end
|
