diff options
Diffstat (limited to 'arch/m68k/fpsp040/x_store.S')
| -rw-r--r-- | arch/m68k/fpsp040/x_store.S | 256 |
1 files changed, 256 insertions, 0 deletions
diff --git a/arch/m68k/fpsp040/x_store.S b/arch/m68k/fpsp040/x_store.S new file mode 100644 index 00000000000..4282fa67d44 --- /dev/null +++ b/arch/m68k/fpsp040/x_store.S @@ -0,0 +1,256 @@ +| +| x_store.sa 3.2 1/24/91 +| +| store --- store operand to memory or register +| +| Used by underflow and overflow handlers. +| +| a6 = points to fp value to be stored. +| + +| Copyright (C) Motorola, Inc. 1990 +| All Rights Reserved +| +| THIS IS UNPUBLISHED PROPRIETARY SOURCE CODE OF MOTOROLA +| The copyright notice above does not evidence any +| actual or intended publication of such source code.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_STORE: |idnt 2,1 | Motorola 040 Floating Point Software Package + + |section 8 + +fpreg_mask: + .byte 0x80,0x40,0x20,0x10,0x08,0x04,0x02,0x01 + +#include "fpsp.h" + + |xref mem_write + |xref get_fline + |xref g_opcls + |xref g_dfmtou + |xref reg_dest + + .global dest_ext + .global dest_dbl + .global dest_sgl + + .global store +store: + btstb #E3,E_BYTE(%a6) + beqs E1_sto +E3_sto: + movel CMDREG3B(%a6),%d0 + bfextu %d0{#6:#3},%d0 |isolate dest. reg from cmdreg3b +sto_fp: + lea fpreg_mask,%a1 + moveb (%a1,%d0.w),%d0 |convert reg# to dynamic register mask + tstb LOCAL_SGN(%a0) + beqs is_pos + bsetb #sign_bit,LOCAL_EX(%a0) +is_pos: + fmovemx (%a0),%d0 |move to correct register +| +| if fp0-fp3 is being modified, we must put a copy +| in the USER_FPn variable on the stack because all exception +| handlers restore fp0-fp3 from there. +| + cmpb #0x80,%d0 + bnes not_fp0 + fmovemx %fp0-%fp0,USER_FP0(%a6) + rts +not_fp0: + cmpb #0x40,%d0 + bnes not_fp1 + fmovemx %fp1-%fp1,USER_FP1(%a6) + rts +not_fp1: + cmpb #0x20,%d0 + bnes not_fp2 + fmovemx %fp2-%fp2,USER_FP2(%a6) + rts +not_fp2: + cmpb #0x10,%d0 + bnes not_fp3 + fmovemx %fp3-%fp3,USER_FP3(%a6) + rts +not_fp3: + rts + +E1_sto: + bsrl g_opcls |returns opclass in d0 + cmpib #3,%d0 + beq opc011 |branch if opclass 3 + movel CMDREG1B(%a6),%d0 + bfextu %d0{#6:#3},%d0 |extract destination register + bras sto_fp + +opc011: + bsrl g_dfmtou |returns dest format in d0 +| ;ext=00, sgl=01, dbl=10 + movel %a0,%a1 |save source addr in a1 + movel EXC_EA(%a6),%a0 |get the address + cmpil #0,%d0 |if dest format is extended + beq dest_ext |then branch + cmpil #1,%d0 |if dest format is single + beq dest_sgl |then branch +| +| fall through to dest_dbl +| + +| +| dest_dbl --- write double precision value to user space +| +|Input +| a0 -> destination address +| a1 -> source in extended precision +|Output +| a0 -> destroyed +| a1 -> destroyed +| d0 -> 0 +| +|Changes extended precision to double precision. +| Note: no attempt is made to round the extended value to double. +| dbl_sign = ext_sign +| dbl_exp = ext_exp - $3fff(ext bias) + $7ff(dbl bias) +| get rid of ext integer bit +| dbl_mant = ext_mant{62:12} +| +| --------------- --------------- --------------- +| extended -> |s| exp | |1| ms mant | | ls mant | +| --------------- --------------- --------------- +| 95 64 63 62 32 31 11 0 +| | | +| | | +| | | +| v v +| --------------- --------------- +| double -> |s|exp| mant | | mant | +| --------------- --------------- +| 63 51 32 31 0 +| +dest_dbl: + clrl %d0 |clear d0 + movew LOCAL_EX(%a1),%d0 |get exponent + subw #0x3fff,%d0 |subtract extended precision bias + cmpw #0x4000,%d0 |check if inf + beqs inf |if so, special case + addw #0x3ff,%d0 |add double precision bias + swap %d0 |d0 now in upper word + lsll #4,%d0 |d0 now in proper place for dbl prec exp + tstb LOCAL_SGN(%a1) + beqs get_mant |if positive, go process mantissa + bsetl #31,%d0 |if negative, put in sign information +| ; before continuing + bras get_mant |go process mantissa +inf: + movel #0x7ff00000,%d0 |load dbl inf exponent + clrl LOCAL_HI(%a1) |clear msb + tstb LOCAL_SGN(%a1) + beqs dbl_inf |if positive, go ahead and write it + bsetl #31,%d0 |if negative put in sign information +dbl_inf: + movel %d0,LOCAL_EX(%a1) |put the new exp back on the stack + bras dbl_wrt +get_mant: + movel LOCAL_HI(%a1),%d1 |get ms mantissa + bfextu %d1{#1:#20},%d1 |get upper 20 bits of ms + orl %d1,%d0 |put these bits in ms word of double + movel %d0,LOCAL_EX(%a1) |put the new exp back on the stack + movel LOCAL_HI(%a1),%d1 |get ms mantissa + movel #21,%d0 |load shift count + lsll %d0,%d1 |put lower 11 bits in upper bits + movel %d1,LOCAL_HI(%a1) |build lower lword in memory + movel LOCAL_LO(%a1),%d1 |get ls mantissa + bfextu %d1{#0:#21},%d0 |get ls 21 bits of double + orl %d0,LOCAL_HI(%a1) |put them in double result +dbl_wrt: + movel #0x8,%d0 |byte count for double precision number + exg %a0,%a1 |a0=supervisor source, a1=user dest + bsrl mem_write |move the number to the user's memory + rts +| +| dest_sgl --- write single precision value to user space +| +|Input +| a0 -> destination address +| a1 -> source in extended precision +| +|Output +| a0 -> destroyed +| a1 -> destroyed +| d0 -> 0 +| +|Changes extended precision to single precision. +| sgl_sign = ext_sign +| sgl_exp = ext_exp - $3fff(ext bias) + $7f(sgl bias) +| get rid of ext integer bit +| sgl_mant = ext_mant{62:12} +| +| --------------- --------------- --------------- +| extended -> |s| exp | |1| ms mant | | ls mant | +| --------------- --------------- --------------- +| 95 64 63 62 40 32 31 12 0 +| | | +| | | +| | | +| v v +| --------------- +| single -> |s|exp| mant | +| --------------- +| 31 22 0 +| +dest_sgl: + clrl %d0 + movew LOCAL_EX(%a1),%d0 |get exponent + subw #0x3fff,%d0 |subtract extended precision bias + cmpw #0x4000,%d0 |check if inf + beqs sinf |if so, special case + addw #0x7f,%d0 |add single precision bias + swap %d0 |put exp in upper word of d0 + lsll #7,%d0 |shift it into single exp bits + tstb LOCAL_SGN(%a1) + beqs get_sman |if positive, continue + bsetl #31,%d0 |if negative, put in sign first + bras get_sman |get mantissa +sinf: + movel #0x7f800000,%d0 |load single inf exp to d0 + tstb LOCAL_SGN(%a1) + beqs sgl_wrt |if positive, continue + bsetl #31,%d0 |if negative, put in sign info + bras sgl_wrt + +get_sman: + movel LOCAL_HI(%a1),%d1 |get ms mantissa + bfextu %d1{#1:#23},%d1 |get upper 23 bits of ms + orl %d1,%d0 |put these bits in ms word of single + +sgl_wrt: + movel %d0,L_SCR1(%a6) |put the new exp back on the stack + movel #0x4,%d0 |byte count for single precision number + tstl %a0 |users destination address + beqs sgl_Dn |destination is a data register + exg %a0,%a1 |a0=supervisor source, a1=user dest + leal L_SCR1(%a6),%a0 |point a0 to data + bsrl mem_write |move the number to the user's memory + rts +sgl_Dn: + bsrl get_fline |returns fline word in d0 + andw #0x7,%d0 |isolate register number + movel %d0,%d1 |d1 has size:reg formatted for reg_dest + orl #0x10,%d1 |reg_dest wants size added to reg# + bral reg_dest |size is X, rts in reg_dest will +| ;return to caller of dest_sgl + +dest_ext: + tstb LOCAL_SGN(%a1) |put back sign into exponent word + beqs dstx_cont + bsetb #sign_bit,LOCAL_EX(%a1) +dstx_cont: + clrb LOCAL_SGN(%a1) |clear out the sign byte + + movel #0x0c,%d0 |byte count for extended number + exg %a0,%a1 |a0=supervisor source, a1=user dest + bsrl mem_write |move the number to the user's memory + rts + + |end |