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276 lines
6.5 KiB
276 lines
6.5 KiB
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| x_snan.sa 3.3 7/1/91 |
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| fpsp_snan --- FPSP handler for signalling NAN exception |
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| SNAN for float -> integer conversions (integer conversion of |
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| an SNAN) is a non-maskable run-time exception. |
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| For trap disabled the 040 does the following: |
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| If the dest data format is s, d, or x, then the SNAN bit in the NAN |
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| is set to one and the resulting non-signaling NAN (truncated if |
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| necessary) is transferred to the dest. If the dest format is b, w, |
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| or l, then garbage is written to the dest (actually the upper 32 bits |
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| of the mantissa are sent to the integer unit). |
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| |
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| For trap enabled the 040 does the following: |
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| If the inst is move_out, then the results are the same as for trap |
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| disabled with the exception posted. If the instruction is not move_ |
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| out, the dest. is not modified, and the exception is posted. |
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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_SNAN: |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 get_fline |
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|xref mem_write |
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|xref real_snan |
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|xref real_inex |
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|xref fpsp_done |
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|xref reg_dest |
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.global fpsp_snan |
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fpsp_snan: |
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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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fmovemx %fp0-%fp3,USER_FP0(%a6) |
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fmoveml %fpcr/%fpsr/%fpiar,USER_FPCR(%a6) |
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| Check if trap enabled |
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btstb #snan_bit,FPCR_ENABLE(%a6) |
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bnes ena |If enabled, then branch |
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bsrl move_out |else SNAN disabled |
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| |
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| It is possible to have an inex1 exception with the |
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| snan. If the inex enable bit is set in the FPCR, and either |
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| inex2 or inex1 occurred, we must clean up and branch to the |
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| real inex handler. |
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ck_inex: |
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moveb FPCR_ENABLE(%a6),%d0 |
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andb FPSR_EXCEPT(%a6),%d0 |
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andib #0x3,%d0 |
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beq end_snan |
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| Inexact enabled and reported, and we must take an inexact exception. |
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take_inex: |
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moveb #INEX_VEC,EXC_VEC+1(%a6) |
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moveml USER_DA(%a6),%d0-%d1/%a0-%a1 |
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fmovemx USER_FP0(%a6),%fp0-%fp3 |
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fmoveml USER_FPCR(%a6),%fpcr/%fpsr/%fpiar |
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frestore (%a7)+ |
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unlk %a6 |
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bral real_inex |
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| SNAN is enabled. Check if inst is move_out. |
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| Make any corrections to the 040 output as necessary. |
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ena: |
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btstb #5,CMDREG1B(%a6) |if set, inst is move out |
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beq not_out |
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bsrl move_out |
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report_snan: |
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moveb (%a7),VER_TMP(%a6) |
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cmpib #VER_40,(%a7) |test for orig unimp frame |
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bnes ck_rev |
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moveql #13,%d0 |need to zero 14 lwords |
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bras rep_con |
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ck_rev: |
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moveql #11,%d0 |need to zero 12 lwords |
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rep_con: |
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clrl (%a7) |
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loop1: |
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clrl -(%a7) |clear and dec a7 |
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dbra %d0,loop1 |
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moveb VER_TMP(%a6),(%a7) |format a busy frame |
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moveb #BUSY_SIZE-4,1(%a7) |
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movel USER_FPSR(%a6),FPSR_SHADOW(%a6) |
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orl #sx_mask,E_BYTE(%a6) |
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moveml USER_DA(%a6),%d0-%d1/%a0-%a1 |
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fmovemx USER_FP0(%a6),%fp0-%fp3 |
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fmoveml USER_FPCR(%a6),%fpcr/%fpsr/%fpiar |
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frestore (%a7)+ |
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unlk %a6 |
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bral real_snan |
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| Exit snan handler by expanding the unimp frame into a busy frame |
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end_snan: |
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bclrb #E1,E_BYTE(%a6) |
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moveb (%a7),VER_TMP(%a6) |
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cmpib #VER_40,(%a7) |test for orig unimp frame |
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bnes ck_rev2 |
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moveql #13,%d0 |need to zero 14 lwords |
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bras rep_con2 |
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ck_rev2: |
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moveql #11,%d0 |need to zero 12 lwords |
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rep_con2: |
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clrl (%a7) |
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loop2: |
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clrl -(%a7) |clear and dec a7 |
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dbra %d0,loop2 |
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moveb VER_TMP(%a6),(%a7) |format a busy frame |
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moveb #BUSY_SIZE-4,1(%a7) |write busy size |
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movel USER_FPSR(%a6),FPSR_SHADOW(%a6) |
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orl #sx_mask,E_BYTE(%a6) |
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moveml USER_DA(%a6),%d0-%d1/%a0-%a1 |
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fmovemx USER_FP0(%a6),%fp0-%fp3 |
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fmoveml USER_FPCR(%a6),%fpcr/%fpsr/%fpiar |
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frestore (%a7)+ |
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unlk %a6 |
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bral fpsp_done |
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| Move_out |
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move_out: |
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movel EXC_EA(%a6),%a0 |get <ea> from exc frame |
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bfextu CMDREG1B(%a6){#3:#3},%d0 |move rx field to d0{2:0} |
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cmpil #0,%d0 |check for long |
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beqs sto_long |branch if move_out long |
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cmpil #4,%d0 |check for word |
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beqs sto_word |branch if move_out word |
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cmpil #6,%d0 |check for byte |
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beqs sto_byte |branch if move_out byte |
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| Not byte, word or long |
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rts |
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| Get the 32 most significant bits of etemp mantissa |
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sto_long: |
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movel ETEMP_HI(%a6),%d1 |
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movel #4,%d0 |load byte count |
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| Set signalling nan bit |
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bsetl #30,%d1 |
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| Store to the users destination address |
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tstl %a0 |check if <ea> is 0 |
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beqs wrt_dn |destination is a data register |
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movel %d1,-(%a7) |move the snan onto the stack |
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movel %a0,%a1 |load dest addr into a1 |
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movel %a7,%a0 |load src addr of snan into a0 |
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bsrl mem_write |write snan to user memory |
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movel (%a7)+,%d1 |clear off stack |
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rts |
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| Get the 16 most significant bits of etemp mantissa |
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sto_word: |
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movel ETEMP_HI(%a6),%d1 |
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movel #2,%d0 |load byte count |
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| Set signalling nan bit |
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bsetl #30,%d1 |
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| Store to the users destination address |
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tstl %a0 |check if <ea> is 0 |
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beqs wrt_dn |destination is a data register |
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movel %d1,-(%a7) |move the snan onto the stack |
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movel %a0,%a1 |load dest addr into a1 |
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movel %a7,%a0 |point to low word |
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bsrl mem_write |write snan to user memory |
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movel (%a7)+,%d1 |clear off stack |
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rts |
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| Get the 8 most significant bits of etemp mantissa |
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sto_byte: |
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movel ETEMP_HI(%a6),%d1 |
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movel #1,%d0 |load byte count |
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| Set signalling nan bit |
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bsetl #30,%d1 |
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| Store to the users destination address |
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tstl %a0 |check if <ea> is 0 |
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beqs wrt_dn |destination is a data register |
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movel %d1,-(%a7) |move the snan onto the stack |
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movel %a0,%a1 |load dest addr into a1 |
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movel %a7,%a0 |point to source byte |
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bsrl mem_write |write snan to user memory |
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movel (%a7)+,%d1 |clear off stack |
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rts |
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| wrt_dn --- write to a data register |
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| We get here with D1 containing the data to write and D0 the |
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| number of bytes to write: 1=byte,2=word,4=long. |
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wrt_dn: |
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movel %d1,L_SCR1(%a6) |data |
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movel %d0,-(%a7) |size |
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bsrl get_fline |returns fline word in d0 |
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movel %d0,%d1 |
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andil #0x7,%d1 |d1 now holds register number |
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movel (%sp)+,%d0 |get original size |
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cmpil #4,%d0 |
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beqs wrt_long |
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cmpil #2,%d0 |
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bnes wrt_byte |
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wrt_word: |
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orl #0x8,%d1 |
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bral reg_dest |
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wrt_long: |
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orl #0x10,%d1 |
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bral reg_dest |
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wrt_byte: |
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bral reg_dest |
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| Check if it is a src nan or dst nan |
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not_out: |
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movel DTAG(%a6),%d0 |
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bfextu %d0{#0:#3},%d0 |isolate dtag in lsbs |
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cmpib #3,%d0 |check for nan in destination |
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bnes issrc |destination nan has priority |
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dst_nan: |
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btstb #6,FPTEMP_HI(%a6) |check if dest nan is an snan |
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bnes issrc |no, so check source for snan |
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movew FPTEMP_EX(%a6),%d0 |
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bras cont |
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issrc: |
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movew ETEMP_EX(%a6),%d0 |
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cont: |
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btstl #15,%d0 |test for sign of snan |
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beqs clr_neg |
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bsetb #neg_bit,FPSR_CC(%a6) |
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bra report_snan |
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clr_neg: |
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bclrb #neg_bit,FPSR_CC(%a6) |
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bra report_snan |
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|end
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