| | x_snan.sa 3.3 7/1/91 | | fpsp_snan --- FPSP handler for signalling NAN exception | | SNAN for float -> integer conversions (integer conversion of | an SNAN) is a non-maskable run-time exception. | | For trap disabled the 040 does the following: | If the dest data format is s, d, or x, then the SNAN bit in the NAN | is set to one and the resulting non-signaling NAN (truncated if | necessary) is transferred to the dest. If the dest format is b, w, | or l, then garbage is written to the dest (actually the upper 32 bits | of the mantissa are sent to the integer unit). | | For trap enabled the 040 does the following: | If the inst is move_out, then the results are the same as for trap | disabled with the exception posted. If the instruction is not move_ | out, the dest. is not modified, and the exception is posted. | | Copyright (C) Motorola, Inc. 1990 | All Rights Reserved | | THIS IS UNPUBLISHED PROPRIETARY SOURCE CODE OF MOTOROLA | The copyright notice above does not evidence any | actual or intended publication of such source code. X_SNAN: |idnt 2,1 | Motorola 040 Floating Point Software Package |section 8 #include "fpsp.h" |xref get_fline |xref mem_write |xref real_snan |xref real_inex |xref fpsp_done |xref reg_dest .global fpsp_snan fpsp_snan: link %a6,#-LOCAL_SIZE fsave -(%a7) moveml %d0-%d1/%a0-%a1,USER_DA(%a6) fmovemx %fp0-%fp3,USER_FP0(%a6) fmoveml %fpcr/%fpsr/%fpiar,USER_FPCR(%a6) | | Check if trap enabled | btstb #snan_bit,FPCR_ENABLE(%a6) bnes ena |If enabled, then branch bsrl move_out |else SNAN disabled | | It is possible to have an inex1 exception with the | snan. If the inex enable bit is set in the FPCR, and either | inex2 or inex1 occurred, we must clean up and branch to the | real inex handler. | ck_inex: moveb FPCR_ENABLE(%a6),%d0 andb FPSR_EXCEPT(%a6),%d0 andib #0x3,%d0 beq end_snan | | Inexact enabled and reported, and we must take an inexact exception. | take_inex: moveb #INEX_VEC,EXC_VEC+1(%a6) moveml USER_DA(%a6),%d0-%d1/%a0-%a1 fmovemx USER_FP0(%a6),%fp0-%fp3 fmoveml USER_FPCR(%a6),%fpcr/%fpsr/%fpiar frestore (%a7)+ unlk %a6 bral real_inex | | SNAN is enabled. Check if inst is move_out. | Make any corrections to the 040 output as necessary. | ena: btstb #5,CMDREG1B(%a6) |if set, inst is move out beq not_out bsrl move_out report_snan: moveb (%a7),VER_TMP(%a6) cmpib #VER_40,(%a7) |test for orig unimp frame bnes ck_rev moveql #13,%d0 |need to zero 14 lwords bras rep_con ck_rev: moveql #11,%d0 |need to zero 12 lwords rep_con: clrl (%a7) loop1: clrl -(%a7) |clear and dec a7 dbra %d0,loop1 moveb VER_TMP(%a6),(%a7) |format a busy frame moveb #BUSY_SIZE-4,1(%a7) movel USER_FPSR(%a6),FPSR_SHADOW(%a6) orl #sx_mask,E_BYTE(%a6) moveml USER_DA(%a6),%d0-%d1/%a0-%a1 fmovemx USER_FP0(%a6),%fp0-%fp3 fmoveml USER_FPCR(%a6),%fpcr/%fpsr/%fpiar frestore (%a7)+ unlk %a6 bral real_snan | | Exit snan handler by expanding the unimp frame into a busy frame | end_snan: bclrb #E1,E_BYTE(%a6) moveb (%a7),VER_TMP(%a6) cmpib #VER_40,(%a7) |test for orig unimp frame bnes ck_rev2 moveql #13,%d0 |need to zero 14 lwords bras rep_con2 ck_rev2: moveql #11,%d0 |need to zero 12 lwords rep_con2: clrl (%a7) loop2: clrl -(%a7) |clear and dec a7 dbra %d0,loop2 moveb VER_TMP(%a6),(%a7) |format a busy frame moveb #BUSY_SIZE-4,1(%a7) |write busy size movel USER_FPSR(%a6),FPSR_SHADOW(%a6) orl #sx_mask,E_BYTE(%a6) moveml USER_DA(%a6),%d0-%d1/%a0-%a1 fmovemx USER_FP0(%a6),%fp0-%fp3 fmoveml USER_FPCR(%a6),%fpcr/%fpsr/%fpiar frestore (%a7)+ unlk %a6 bral fpsp_done | | Move_out | move_out: movel EXC_EA(%a6),%a0 |get <ea> from exc frame bfextu CMDREG1B(%a6){#3:#3},%d0 |move rx field to d0{2:0} cmpil #0,%d0 |check for long beqs sto_long |branch if move_out long cmpil #4,%d0 |check for word beqs sto_word |branch if move_out word cmpil #6,%d0 |check for byte beqs sto_byte |branch if move_out byte | | Not byte, word or long | rts | | Get the 32 most significant bits of etemp mantissa | sto_long: movel ETEMP_HI(%a6),%d1 movel #4,%d0 |load byte count | | Set signalling nan bit | bsetl #30,%d1 | | Store to the users destination address | tstl %a0 |check if <ea> is 0 beqs wrt_dn |destination is a data register movel %d1,-(%a7) |move the snan onto the stack movel %a0,%a1 |load dest addr into a1 movel %a7,%a0 |load src addr of snan into a0 bsrl mem_write |write snan to user memory movel (%a7)+,%d1 |clear off stack rts | | Get the 16 most significant bits of etemp mantissa | sto_word: movel ETEMP_HI(%a6),%d1 movel #2,%d0 |load byte count | | Set signalling nan bit | bsetl #30,%d1 | | Store to the users destination address | tstl %a0 |check if <ea> is 0 beqs wrt_dn |destination is a data register movel %d1,-(%a7) |move the snan onto the stack movel %a0,%a1 |load dest addr into a1 movel %a7,%a0 |point to low word bsrl mem_write |write snan to user memory movel (%a7)+,%d1 |clear off stack rts | | Get the 8 most significant bits of etemp mantissa | sto_byte: movel ETEMP_HI(%a6),%d1 movel #1,%d0 |load byte count | | Set signalling nan bit | bsetl #30,%d1 | | Store to the users destination address | tstl %a0 |check if <ea> is 0 beqs wrt_dn |destination is a data register movel %d1,-(%a7) |move the snan onto the stack movel %a0,%a1 |load dest addr into a1 movel %a7,%a0 |point to source byte bsrl mem_write |write snan to user memory movel (%a7)+,%d1 |clear off stack rts | | wrt_dn --- write to a data register | | We get here with D1 containing the data to write and D0 the | number of bytes to write: 1=byte,2=word,4=long. | wrt_dn: movel %d1,L_SCR1(%a6) |data movel %d0,-(%a7) |size bsrl get_fline |returns fline word in d0 movel %d0,%d1 andil #0x7,%d1 |d1 now holds register number movel (%sp)+,%d0 |get original size cmpil #4,%d0 beqs wrt_long cmpil #2,%d0 bnes wrt_byte wrt_word: orl #0x8,%d1 bral reg_dest wrt_long: orl #0x10,%d1 bral reg_dest wrt_byte: bral reg_dest | | Check if it is a src nan or dst nan | not_out: movel DTAG(%a6),%d0 bfextu %d0{#0:#3},%d0 |isolate dtag in lsbs cmpib #3,%d0 |check for nan in destination bnes issrc |destination nan has priority dst_nan: btstb #6,FPTEMP_HI(%a6) |check if dest nan is an snan bnes issrc |no, so check source for snan movew FPTEMP_EX(%a6),%d0 bras cont issrc: movew ETEMP_EX(%a6),%d0 cont: btstl #15,%d0 |test for sign of snan beqs clr_neg bsetb #neg_bit,FPSR_CC(%a6) bra report_snan clr_neg: bclrb #neg_bit,FPSR_CC(%a6) bra report_snan |end