1/* 2 * Copyright (c) 1986, 1993 3 * The Regents of the University of California. All rights reserved. 4 * 5 * This code is derived from software contributed to Berkeley by 6 * Computer Consoles Inc. 7 * 8 * %sccs.include.redist.c% 9 */ 10 11#if defined(SYSLIBC_SCCS) && !defined(lint) 12 .asciz "@(#)cvtfl.s 8.1 (Berkeley) 06/04/93" 13#endif /* SYSLIBC_SCCS and not lint */ 14 15#include <tahoemath/fp.h> 16#include "DEFS.h" 17 18XENTRY(cvtfu, R2|R3|R4|R5) 19 jbr 1f 20 21XENTRY(cvtfl, R2|R3|R4|R5) 22 # 23 #Some initializations: 24 # 251: 26 movl 4(fp),r0 # fetch operand. 27 clrl r3 # r3 - negative flag. 28 # 29 #get exponent 30 # 31 andl3 $EXPMASK,r0,r2 # r2 will hold the exponent. 32 jeql is_reserved # check for reserved operand. 33 cmpl $ONE_EXP,r2 # if exponent is less then 1,return zero. 34 jgtr retzero 35 andl2 $0!EXPSIGN,r2 # turn off biased exponent sign 36 shrl $EXPSHIFT,r2,r2 37 # 38 #get fraction 39 # 40 bbc $31,r0,positive # if negative remember it. 41 incl r3 42positive: 43 # clear the non fraction parts. 44 andl2 $(0!(EXPMASK | SIGNBIT)),r0 45 # add the hidden bit. 46 orl2 $(0!CLEARHID),r0 47 subl2 $24,r2 # compute the shift. 48 jgtr shift_left 49 mnegl r2,r2 50 shrl r2,r0,r0 # shift right. 51 jmp shifted 52shift_left: 53 cmpl r2,$7 54 jgtr overflow 55go_on: shll r2,r0,r0 # shift right. 56shifted: 57 bbc $0,r3,done # check for negative 58 mnegl r0,r0 59done: 60 ret 61 62retzero: 63 clrl r0 64 ret 65overflow: 66 callf $4,sfpover 67 jmp go_on 68 69is_reserved: 70 bbc $31,r0,retzero 71 72 callf $4,sfpresop 73 ret 74