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| x_fline.sa 3.3 1/10/91
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| fpsp_fline --- FPSP handler for fline exception
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| First determine if the exception is one of the unimplemented
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| floating point instructions. If so, let fpsp_unimp handle it.
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| Next, determine if the instruction is an fmovecr with a non-zero
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| <ea> field. If so, handle here and return. Otherwise, it
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| must be a real F-line exception.
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| Copyright (C) Motorola, Inc. 1990
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| All Rights Reserved
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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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X_FLINE: |idnt 2,1 | Motorola 040 Floating Point Software Package
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|section 8
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#include "fpsp.h"
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|xref real_fline
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|xref fpsp_unimp
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|xref uni_2
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|xref mem_read
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|xref fpsp_fmt_error
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.global fpsp_fline
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fpsp_fline:
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| check for unimplemented vector first. Use EXC_VEC-4 because
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| the equate is valid only after a 'link a6' has pushed one more
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| long onto the stack.
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cmpw #UNIMP_VEC,EXC_VEC-4(%a7)
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beql fpsp_unimp
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| fmovecr with non-zero <ea> handling here
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subl #4,%a7 |4 accounts for 2-word difference
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| ;between six word frame (unimp) and
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| ;four word frame
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link %a6,#-LOCAL_SIZE
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fsave -(%a7)
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moveml %d0-%d1/%a0-%a1,USER_DA(%a6)
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moveal EXC_PC+4(%a6),%a0 |get address of fline instruction
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leal L_SCR1(%a6),%a1 |use L_SCR1 as scratch
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movel #4,%d0
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addl #4,%a6 |to offset the sub.l #4,a7 above so that
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| ;a6 can point correctly to the stack frame
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| ;before branching to mem_read
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bsrl mem_read
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subl #4,%a6
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movel L_SCR1(%a6),%d0 |d0 contains the fline and command word
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bfextu %d0{#4:#3},%d1 |extract coprocessor id
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cmpib #1,%d1 |check if cpid=1
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bne not_mvcr |exit if not
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bfextu %d0{#16:#6},%d1
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cmpib #0x17,%d1 |check if it is an FMOVECR encoding
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bne not_mvcr
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| ;if an FMOVECR instruction, fix stack
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| ;and go to FPSP_UNIMP
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fix_stack:
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cmpib #VER_40,(%a7) |test for orig unimp frame
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bnes ck_rev
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subl #UNIMP_40_SIZE-4,%a7 |emulate an orig fsave
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moveb #VER_40,(%a7)
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moveb #UNIMP_40_SIZE-4,1(%a7)
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clrw 2(%a7)
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bras fix_con
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ck_rev:
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cmpib #VER_41,(%a7) |test for rev unimp frame
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bnel fpsp_fmt_error |if not $40 or $41, exit with error
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subl #UNIMP_41_SIZE-4,%a7 |emulate a rev fsave
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moveb #VER_41,(%a7)
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moveb #UNIMP_41_SIZE-4,1(%a7)
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clrw 2(%a7)
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fix_con:
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movew EXC_SR+4(%a6),EXC_SR(%a6) |move stacked sr to new position
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movel EXC_PC+4(%a6),EXC_PC(%a6) |move stacked pc to new position
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fmovel EXC_PC(%a6),%FPIAR |point FPIAR to fline inst
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movel #4,%d1
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addl %d1,EXC_PC(%a6) |increment stacked pc value to next inst
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movew #0x202c,EXC_VEC(%a6) |reformat vector to unimp
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clrl EXC_EA(%a6) |clear the EXC_EA field
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movew %d0,CMDREG1B(%a6) |move the lower word into CMDREG1B
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clrl E_BYTE(%a6)
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bsetb #UFLAG,T_BYTE(%a6)
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moveml USER_DA(%a6),%d0-%d1/%a0-%a1 |restore data registers
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bral uni_2
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not_mvcr:
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moveml USER_DA(%a6),%d0-%d1/%a0-%a1 |restore data registers
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frestore (%a7)+
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unlk %a6
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addl #4,%a7
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bral real_fline
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|end
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