1#ifdef LIBC_SCCS 2 .asciz "@(#)cvtud.s 1.1 (Berkeley/CCI) 07/02/86" 3#endif LIBC_SCCS 4 5#include <tahoemath/fp.h> 6#include "DEFS.h" 7 8XENTRY(cvtud, R2|R3|R4|R5) 9 # 10 # Some initializations: 11 # 12 clrl r2 # r2 - exponent. 13 movl 4(fp),r0 # fetch operand. 14 jeql retzero # return zero. 15 # 16 # Compute exponent: 17 # 18positive: 19 ffs r0,r1 20 incl r1 21 addl2 r1,r2 22 shrl r1,r0,r0 23 jneq positive # look for more set bits. 24 # 25 # we have the exponent in r2. 26 # 27 movl 4(fp),r0 # r0,r1 will hold the resulting f.p. number. 28 clrl r1 29 # 30 # Shift the fraction part to its proper place: 31 # 32 subl3 r2,$HID_POS,r3 33 jlss shiftr # if less then zero we have to shift right. 34 shll r3,r0,r0 # else we shift left. 35 jmp shifted 36shiftr: 37 mnegl r3,r3 38 shrq r3,r0,r0 39shifted: 40 andl2 $CLEARHID,r0 # clear the hidden bit. 41 shal $EXPSHIFT,r2,r2 # shift the exponent to its proper place. 42 orl2 $EXPSIGN,r2 # set the exponent sign bit(to bias it). 43 orl2 r2,r0 # combine exponent & fraction. 44sign_ok: 45 ret 46 47retzero: 48 clrl r0 49 clrl r1 50 ret 51 52 53