.data .asciz "@(#)Ffltd.s 1.1 86/02/03 Copyr 1985 Sun Micro" .even .text | Copyright (c) 1985 by Sun Microsystems, Inc. /* * double-precision floating math run-time support * * copyright 1981, 1982 Richard E. James III * translated to SUN idiom 10/11 March 1983 rt * parameter passing re-done 22 July 1983 rt */ #include "fpcrtdefs.h" SAVEMASK = 0x3c00 RESTMASK = 0x003c /* * type conversion operators * * integer-to-double conversion: fflti * input: * d0 integer * output: * d0/d1 double floating value */ RTENTRY(Ffltd) movel d0,a0 | a0 saves x. movel d2,a1 | a1 saves d2. movel #0x41e,d2 | d2 accumulates exponent. tstl d0 bpls 3f | Branch if x is non-negative. negl d0 | d0 gets abs(x). 3: bmis 2f | Branch if d0 is normalized. bnes 1f | Branch if x not zero. clrl d1 bras Ffltddone | Branch if zero. 1: subqw #1,d2 | Adjust exponent. lsll #1,d0 | Normalize. bpls 1b | Branch if already normalized. 2: bclr #31,d0 | Clear I bit. movel d0,d1 | d1 gets significand. lsrl #8,d0 | Align high order bits. lsrl #3,d0 | Align high order bits. swap d2 lsll #4,d2 | Align exponent. orl d2,d0 | Stick exponent. movel #21,d2 lsll d2,d1 | Align low order bits. cmpl #0,a0 bges Ffltddone | Branch if x was non-negative. bset #31,d0 | Set sign if negative. Ffltddone: movel a1,d2 | Restore d2. RET /* * double-to-integer conversion: ffixi * input: * d0/d1 double floating value * output: * d0 integer */ RTENTRY(Fintd) moveml d2-d3,sp@- movel d0,d3 | d3 gets top(x). bclr #31,d0 | d0 gets top(abs(x)). cmpl #0x3ff00000,d0 bges 1f | Branch if abs(x) >= 1. clrl d0 bras Fintddone 1: cmpl #0x41f00000,d0 blts 2f | Branch if 1 <= |x| < 2**32. movel #0x80000000,d0 | Maximum negative integer. bras Fintddone 2: movel d0,d2 | d2 gets abs(x). andl #0xfffff,d0 | Clear sign and exponent. bset #20,d0 | Set I bit. roll #8,d2 roll #4,d2 andw #0xfff,d2 | d2 gets biased exponent. subw #0x3ff+20,d2 bges 3f | Branch if exp >= 20. negw d2 lsrl d2,d0 bras Fintdsign 3: beqs Fintdsign | Branch if exponent = 20 exactly. lsll d2,d0 | Upper shift. negw d2 addw #32,d2 | Compute right shift. lsrl d2,d1 | This part goes from lower to upper. orl d1,d0 Fintdsign: tstl d3 bpls Fintddone | Branch if x was not negative. negl d0 Fintddone: moveml sp@+,d2-d3 RET RTENTRY(Fnintd) moveml d2-d4,sp@- movel d0,d3 | d3 gets top(x). bclr #31,d0 | d0 gets top(abs(x)). cmpl #0x3fe00000,d0 bges 1f | Branch if abs(x) >= 0.5. clrl d0 bras Fnintddone 1: cmpl #0x41f00000,d0 blts 2f | Branch if 0.5 <= |x| < 2**32. movel #0x80000000,d0 | Maximum negative integer. bras Fnintddone 2: movel d0,d2 | d2 gets abs(x). andl #0xfffff,d0 | Clear sign and exponent. bset #20,d0 | Set I bit. roll #8,d2 roll #4,d2 andw #0xfff,d2 | d2 gets biased exponent. subw #0x3ff+20,d2 bges 3f | Branch if exp >= 20. negw d2 subqw #1,d2 lsrl d2,d0 | Upper part. addql #1,d0 | Round bit. lsrl #1,d0 | Finish shift. bras Fnintdsign 3: beqs Fnintdround | Branch if exponent = 20 exactly. movel d1,d4 | d4 will get lower to upper part. lsll d2,d0 | Upper shift. lsll d2,d1 | Lower shift. negw d2 addw #32,d2 | Compute right shift. lsrl d2,d4 | This part goes from lower to upper. orl d4,d0 Fnintdround: addl #0x80000000,d1 bccs Fnintdsign | Branch if no rounding carry propagate. addql #1,d0 Fnintdsign: tstl d3 bpls Fnintddone | Branch if x was not negative. negl d0 Fnintddone: moveml sp@+,d2-d4 RET RTENTRY(Frintd) moveml d2-d4,sp@- movel d0,d3 | d3 gets top(x). bclr #31,d0 | d0 gets top(abs(x)). cmpl #0x3fe00000,d0 bges 1f | Branch if abs(x) >= 0.5. clrl d0 bras Fnintddone 1: cmpl #0x41f00000,d0 blts 2f | Branch if 0.5 <= |x| < 2**32. movel #0x80000000,d0 | Maximum negative integer. bras Fnintddone 2: movel d0,d2 | d2 gets abs(x). andl #0xfffff,d0 | Clear sign and exponent. bset #20,d0 | Set I bit. roll #8,d2 roll #4,d2 andw #0xfff,d2 | d2 gets biased exponent. subw #0x3ff+20,d2 bges 3f | Branch if exp >= 20. movel d1,d4 | d4 saves lower part. movel d0,d1 negw d2 lsrl d2,d0 | Upper part. negw d2 addw #32,d2 lsll d2,d1 | Lower part. tstl d4 beqs Frintdround | Branch if original low part clear. bset #30,d1 | Set sticky bit to influence rounding. bras Frintdround 3: beqs Frintdround | Branch if exponent = 20 exactly. movel d1,d4 | d4 will get lower to upper part. lsll d2,d0 | Upper shift. lsll d2,d1 | Lower shift. negw d2 addw #32,d2 | Compute right shift. lsrl d2,d4 | This part goes from lower to upper. orl d4,d0 Frintdround: addl #0x80000000,d1 jcc Fnintdsign | Branch if no rounding carry propagate. addql #1,d0 tstl d1 jne Fnintdsign | Branch if not ambiguous. bclr #0,d0 | Force round to even. jra Fnintdsign