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+//
+// $Id$
+//
+// 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+// THIS IS UNPUBLISHED PROPRIETARY SOURCE CODE OF MOTOROLA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.defs"
+
+ |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
+ beqs 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