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Length: 2432 (0x980)
Types: TextFile
Names: »FPDIVD.SRC«
└─⟦c9df7130d⟧ Bits:30005915 Pascal MT+ Release 5.2 (Jet-80)
└─ ⟦this⟧ »FPDIVD.SRC«
; floating point divide routine ; NAME FPDIVD ENTRY FDIVD,FDIVD1 EXT FPERR,MPSUB,DONE2 INCLUDE FPINIT.SRC INCLUDE FPMAC.SRC ; fdivd: setupf ;setup for 2 operands fdivd1: zchk 2 ;check for division by zero jz fperr 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 mov a,op1(x) ;get exponent of op1 inr a ;compensate for algorithm sub op2(x) ;subtract exponent of op2 jv fperr ;floating point error mov op1(x),a ;save exponent of result res sign,op1+msb(x) ;clear sign bits in op1... res sign,op2+msb(x) ;...and op2 lxi h,-nbytes ;add extra variable to stack dad s ;for use in intermediate sphl ;calculations push h ;save addr of lsb xra a ;zero temporary variable mvi b,nbytes ;zero correct number of bytes zerlp: mov m,a ;zero this byte inx h ;bump pointer djnz zerlp ;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 divlp: push d ;save base reg push b ;save counter lxi h,op1 ;get addresses of two operands dad d xchg ;de <- hl = addr( op1 ) lxi b,op2 dad b ;hl = addr( op2 ) mvi b,fracln ;process at most all bytes divd1: dcx h ;bump pointers dcx d ldax d ;get byte from op1 cmp m ;compare with byte from op2 jrc divd2 ;too big don't subtract jrnz divd1a ;continue if zero djnz divd1 ;stop when done inr b ;make the next loop do nothing divd1a: dcx h dcx d djnz divd1a inx h inx d divd1b: call mpsub ;subtract divisor from dividend ora a ;clear carry divd2: pop b ;restore counter pop d ;restore base reg push psw ;save carry rotate y,left ;shift result right one bit pop psw ;get carry jrc divd3 ;don't set a bit bset 0,lsb(y) ;set least significant bit divd3: rotate 1,left ;shift dividend left 1 bit djnz divlp ;...and continue lxi h,op1+lsb ;calculate addr of op1 dad d pop d ;get addr of temp variable mvi b,fracln ;and copy to op1 coplp: ldax d ;get byte from temp mov m,a ;store in op1 inx h ;bump pointers inx d djnz coplp ; 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»