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Length: 1920 (0x780)
Types: TextFile
Names: »FMULT.SRC«
└─⟦c9df7130d⟧ Bits:30005915 Pascal MT+ Release 5.2 (Jet-80)
└─ ⟦this⟧ »FMULT.SRC«
; floating point multiply routine ; NAME FMULT ENTRY FMULT EXT FPERR,MPADD,DONE2 INCLUDE FPINIT.SRC INCLUDE FPMAC.SRC ; fmult: setupf ;setup for 2 operands fmult1: mov a,op1+msb(x) ;get sign of op1 xra op2+msb(x) ;x-or with sign of op2 mov scr1(x),a ;save sign of result res sign,op1+msb(x) ;clear both sign bits res sign,op2+msb(x) mov a,op1(x) ;get exponent of op1 add op2(x) ;add exponent of op2 jv fperr ;floating point error mov op1(x),a ;save exponent of result lxi h,-nbytes ;add extra variable to stack dad s ;for use in intermediate sphl ;calculations push x ;save x-reg lxi b,op2+lsb ;make x-reg point to lsb of op2 dadx b xtix push h ;save addr of lsb xra a ;zero temporary variable mvi b,nbytes ;zero correct number of bytes zerlop: mov m,a ;zero this byte inx h ;bump pointer djnz zerlop ;and continue dcx h ;correct pointer push h ;make y point to this pop y ;temporary variable mvi b,fracln*8-1 ;process all bits in mantissa muloop: rotate 1,right ;rotate multiplier right 1 bit jrnc mult1 ;carry out of lsb? pop d ;yes... pop h push h push d push b ;save counter call mpadd ;add multiplicand to result pop b ;restore counter push ix pop d ;restore d mult1: rotate y,right ;shift result right one bit djnz muloop ;...and continue pop d ;get addr of temp variable pop h ;get addr of op2 lxi b,op1-op2 ;calculate addr of op1 dad b mvi b,fracln ;and copy to op1 coplop: ldax d ;get byte from temp mov m,a ;store in op1 inx h ;bump pointers inx d djnz coplop ; fix stack lxi h,nbytes ;size of temp variable dad s ;+ stack pointer sphl ;is original value of sp bit sign,scr1(x) ;fix sign of result jz done2 bset sign,op1+msb(x) jmp done2 ;; «eof»