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1.1 ! root 1: .data ! 2: .asciz "@(#)Faddd.s 1.1 86/02/03 Copyr 1985 Sun Micro" ! 3: .even ! 4: .text ! 5: ! 6: | Copyright (c) 1985 by Sun Microsystems, Inc. ! 7: ! 8: #include "fpcrtdefs.h" ! 9: ! 10: /* ! 11: * double-precision floating math run-time support ! 12: * ! 13: * copyright 1981, 1982 Richard E. James III ! 14: * translated to SUN idiom 10/11 March 1983 rt ! 15: * parameter passing re-done 22 July 1983 rt ! 16: */ ! 17: ! 18: ARG2PTR = a0 ! 19: ! 20: /* ! 21: * extract exponents from two double-precision numbers. ! 22: * ! 23: * input: ! 24: * d0/d1 one operand ! 25: * d2/d3 other operand ! 26: * ! 27: * output: ! 28: * d0/d1 mantissa, waiting for hidden bit to be turned on ! 29: * d2/d3 other mantissa, likewise ! 30: * d6 exponent from d2/d3 ! 31: * d7 exponent for d0/d1 ! 32: * ! 33: * destroys d4 ! 34: */ ! 35: ! 36: ENTER(d_exte) ! 37: moveq #11,d4 | size of exponent ! 38: roll d4,d0 ! 39: roll d4,d2 ! 40: roll d4,d1 ! 41: roll d4,d3 ! 42: movl #0x7ff,d6 ! 43: movl d6,d7 ! 44: andl d2,d6 ! 45: eorl d6,d2 ! 46: movl d7,d4 ! 47: andl d3,d4 ! 48: eorl d4,d3 ! 49: lsrl #1,d2 ! 50: orl d4,d2 ! 51: | end transformation of larger ! 52: movl d7,d4 ! 53: andl d0,d7 ! 54: eorl d7,d0 ! 55: andl d1,d4 ! 56: eorl d4,d1 ! 57: lsrl #1,d0 ! 58: orl d4,d0 ! 59: | end transformation of smaller ! 60: rts ! 61: ! 62: /* ! 63: * ieee double floating compare ! 64: * copyright 1981, Richard E. James III ! 65: * translated to SUN idiom 30 March 1983 rt ! 66: */ ! 67: ! 68: /* ! 69: * entry conditions: ! 70: * first argument in d0/d1 ! 71: * second argument on stack ! 72: * exit conditions: ! 73: * result in cc -- carry flag set if either a NAN ! 74: * problems: ! 75: * unordered cases (e.e.: projective infinities and NANs) ! 76: * produce random results. ! 77: * A NAN, however, does compare not equal to anything. ! 78: * ! 79: * register conventions: ! 80: * d0/d1 first operand ! 81: * d2/d3 second operand ! 82: * d4 scratch ! 83: */ ! 84: SAVEMASK = 0x3800 | registers d2-d4 ! 85: RESTMASK = 0x1c ! 86: NSAVED = 3*4 | 6 registers * sizeof(register) ! 87: CODE = NSAVED ! 88: ! 89: RTENTRY(Fcmpd) ! 90: subqw #2,sp | save room for result ! 91: | save registers and load operands into registers ! 92: moveml #SAVEMASK,sp@- ! 93: movl ARG2PTR@+,d2 ! 94: movl ARG2PTR@ ,d3 ! 95: | we are now set up. ! 96: movl d2,d4 ! 97: andl d0,d4 | compare signs ! 98: bpls nbothmi ! 99: exg d0,d2 | both minus ! 100: exg d1,d3 ! 101: nbothmi:cmpl d2,d0 | main compare ! 102: bnes gotcmp | got the answer ! 103: movl d1,d4 ! 104: subl d3,d4 | compare lowers ! 105: beqs gotcmp | entirely equal ! 106: roxrl #1,d4 ! 107: andb #0xa,cc | clear z, in case differ by 1 ulp ! 108: gotcmp: andb #0xe,cc | clear carry ! 109: bgts 1f ! 110: blts 2f ! 111: movw #FEQ,sp@(CODE) ! 112: bras 3f ! 113: 1: ! 114: movw #FGT,sp@(CODE) ! 115: bras 3f ! 116: 2: ! 117: movw #FLT,sp@(CODE) ! 118: 3: ! 119: lsll #1,d0 ! 120: lsll #1,d2 ! 121: cmpl d2,d0 ! 122: bccs 4$ ! 123: exg d0,d2 | find larger in magnitude ! 124: 4$: cmpl #0xffe00000,d0 ! 125: blss 6$ | no nan ! 126: movw #FUN,sp@(CODE) | c, nz ! 127: bras 8$ | one was a nan ! 128: 6$: orl d1,d0 ! 129: orl d2,d0 ! 130: orl d3,d0 ! 131: bnes 8$ ! 132: movw #FEQ,sp@(CODE) | -0 == 0 ! 133: | done, now go ! 134: 8$: moveml sp@+,#RESTMASK | put back saved registers ! 135: movw sp@+,cc | install condition code ! 136: RET ! 137: ! 138: ! 139: /* ! 140: * ieee double floating add ! 141: * copyright 1981, Richard E. James III ! 142: * translated to SUN idiom 10 March 1983 rt ! 143: */ ! 144: ! 145: /* ! 146: * entry conditions: ! 147: * first argument in d0/d1 ! 148: * second argument on stack ! 149: * exit conditions: ! 150: * result (8 bytes) in d0/d1 ! 151: * ! 152: * register conventions: ! 153: * d0/d1 smaller operand (d0=most significant) ! 154: * d2/d3 larger operand ! 155: * d4 11 or mask of 11 bits ! 156: * d5 signs: sign of .w = sign of answer ! 157: * sign of .b = comparison of signs ! 158: * d6 exponent of larger ! 159: * d7 exponent of smaller ! 160: */ ! 161: SAVEMASK = 0x3f00 | registers d2-d7 ! 162: RESTMASK = 0xfc ! 163: NSAVED = 6*4 | 6 registers * sizeof(register) ! 164: ! 165: RTENTRY(Fsubd) ! 166: | save registers and load operands into registers ! 167: moveml #SAVEMASK,sp@- | registers d2-d7 ! 168: movl ARG2PTR@+,d2 ! 169: movl ARG2PTR@ ,d3 ! 170: bchg #31,d2 ! 171: jra adding ! 172: RTENTRY(Faddd) ! 173: | save registers and load operands into registers ! 174: moveml #SAVEMASK,sp@- | registers d2-d7 ! 175: movl ARG2PTR@+,d2 ! 176: movl ARG2PTR@ ,d3 ! 177: adding: ! 178: | extract signs ! 179: asll #1,d0 | sign ->c ! 180: scs d4 | c -> d4 ! 181: asll #1,d2 ! 182: scs d5 ! 183: | compare and exchange to put larger in d0/d1 ! 184: cmpl d2,d0 ! 185: blss 1$ ! 186: exg d0,d2 ! 187: exg d1,d3 ! 188: exg d4,d5 ! 189: 1$: extw d5 | sign of larger ! 190: eorb d4,d5 | comparison of signs ! 191: | extract exponents ! 192: jbsr d_exte | larger ->d2/d3,d6; smaller ->d0/d1,d7 ! 193: tstw d7 ! 194: bnes 2$ | not zero or denormalized ! 195: | here, smaller is zero or is denormalized ! 196: movl d0,d4 ! 197: orl d1,d4 ! 198: jeq signofzero | if smaller == 0 use larger ! 199: | (sign of 0-0 unpredictable) ! 200: lsll #1,d1 ! 201: roxll #1,d0 ! 202: tstw d6 | larger exp ! 203: bnes 3$ | not gradual underflow ! 204: lsll #1,d3 ! 205: roxll #1,d2 ! 206: bras addorsub | both gradual-underflow, no hidden or align needed ! 207: 2$: bset #31,d0 | add hidden bit ! 208: 3$: cmpw #0x7ff,d6 ! 209: jeq a_ovfl | inf/nan ! 210: bset #31,d2 ! 211: | align smaller ! 212: | shift-by-eight loop ! 213: subw d6,d7 ! 214: negw d7 | d7 = difference of exponents ! 215: cmpw #16,d7 ! 216: jge rsge16 | Branch if shift of 16 or more. ! 217: rs015: | Right shift 0..15. ! 218: subqw #8,d7 ! 219: blts 5$ | exit loop when difference <8 ! 220: ! 221: tstb d1 ! 222: beqs 99$ | Branch if no bits to lose in shift. ! 223: bset #8,d1 | Turn on the sticky bit if any bits will be lost. ! 224: 99$: ! 225: movb d0,d1 | shift eight bits down ! 226: rorl #8,d1 ! 227: lsrl #8,d0 ! 228: bras rs015 ! 229: 5$: addqw #7,d7 ! 230: bmis addorsub ! 231: tstb d1 ! 232: beqs 98$ ! 233: bset #8,d1 | Turn on sticky bit. ! 234: 98$: ! 235: 6$: lsrl #1,d0 ! 236: roxrl #1,d1 ! 237: dbra d7,6$ | final part of alignment ! 238: addorsub: ! 239: | decide whether to add or subtract ! 240: tstb d5 | compare signs ! 241: bmis diff ! 242: | add them ! 243: addl d1,d3 | sum ! 244: addxl d0,d2 ! 245: bccs endas | no c, ok ! 246: roxrl #1,d2 ! 247: roxrl #1,d3 ! 248: addqw #1,d6 ! 249: cmpw #0x7ff,d6 ! 250: blts endas | no overflow ! 251: jra a_geninf ! 252: ! 253: rsge16: | Right shift 16 or more. ! 254: cmpw #32,d7 ! 255: blts rs1631 | Branch if shift is 16..31. ! 256: cmpw #64,d7 ! 257: blts rs3263 | Branch if shift is 32..63. ! 258: clrl d0 | Top will be zero. ! 259: moveq #1,d1 | Bottom will be sticky. ! 260: bras addorsub ! 261: rs3263: | Shift 32. ! 262: tstl d1 ! 263: beqs 1$ ! 264: bset #0,d0 | Sticky bit on. ! 265: 1$: ! 266: movl d0,d1 ! 267: clrl d0 ! 268: subw #32,d7 ! 269: cmpw #16,d7 ! 270: blts rs015 | Branch if shift < 16. ! 271: rs1631: | Shift 16. ! 272: tstw d1 ! 273: beq 2$ | Branch if no bits in D. ! 274: bset #16,d1 | Turn on sticky bit in C. ! 275: 2$: ! 276: clrw d1 | d1 gets Cs,0. ! 277: movw d0,d1 | d1 gets Cs,B. ! 278: swap d1 | d1 gets B,Cs. ! 279: clrw d0 | d0 gets A,0. ! 280: swap d0 | d0 gets 0,A. ! 281: subw #16,d7 ! 282: jra rs015 ! 283: ! 284: ! 285: | subtract then ! 286: diff: subl d1,d3 | subtract lowers ! 287: subxl d0,d2 | subtract uppers ! 288: bccs 9$ ! 289: | cancelled down into 2nd word, but got wrong sign ! 290: notw d5 | flip result sign ! 291: negl d3 ! 292: negxl d2 | negate value ! 293: 9$: bnes subrenorm | Branch if result nonzero. ! 294: tstl d3 ! 295: bnes subrenorm | Branch if result nonzero. ! 296: clrw d5 | Exact zero result has positive sign. ! 297: subrenorm: | Renormalize result after cancellation. ! 298: jbsr d_norm ! 299: | rejoin, round ! 300: endas: jbsr d_rcp | round, check, and pack ! 301: assgn: lslw #1,d5 | get sign ! 302: roxrl #1,d2 | put in sign ! 303: ! 304: | answer is now in d2/d3: put in d0/d1 ! 305: movl d2,d0 ! 306: movl d3,d1 ! 307: asexit: | restore registers and split ! 308: moveml sp@+,#RESTMASK ! 309: RET ! 310: ! 311: | EXCEPTION CASES ! 312: signofzero: | Set up proper sign for exact zero. ! 313: tstb d5 ! 314: beqs useln | Branch if signs equal: either will do. ! 315: tstw d6 ! 316: bnes useln | Branch if not zero or subnormal. ! 317: tstl d2 ! 318: bnes useln | Branch if subnormal. ! 319: tstl d3 ! 320: bnes useln | Branch if subnormal. ! 321: clrw d5 | Signs unequal so set positive. ! 322: ! 323: useln: tstw d6 ! 324: beqs usel | Branch if subnormal: don't set i bit. ! 325: bset #31,d2 | Set i bit of normal number. ! 326: usel: jbsr d_usel | use the larger ! 327: bras assgn ! 328: ! 329: | larger exponent = 1-23 ! 330: a_ovfl: movl d2,d4 | larger mantissa ! 331: orl d3,d4 ! 332: bnes usel | larger = nan, use it ! 333: cmpw d6,d7 | exps ! 334: bnes usel | larger=inf and smaller=number ! 335: | (need nan...) ! 336: tstb d5 | comparison of signs ! 337: bpls usel | inf+inf=inf; inf-inf=nan ! 338: movl #0x7ff00001,d0 | NAN ! 339: clrl d1 ! 340: bras asexit ! 341: | result overflows ! 342: a_geninf: ! 343: movl #0xffe00000,d2 ! 344: clrl d3 ! 345: bras assgn ! 346: ! 347: /* ! 348: * subroutine for unpacking one operand, and normalizing a denormalized number ! 349: * input: ! 350: * d0/d1 number ! 351: * output: ! 352: * d0/d1 mantissa ! 353: * d7.w exponent ! 354: * z on iff mantissa is zero_ ! 355: * ! 356: * unchanged: ! 357: * d4 bottom = 0xf77 ! 358: */ ! 359: ! 360: unp: movl d0,d7 | start getting exp ! 361: andl #0xfffff,d0 | clear out sign and exp ! 362: swap d7 ! 363: lsrw #(16-1-11),d7 ! 364: andw d4,d7 | expondnt ! 365: bnes 3$ | normal number ! 366: | denormalized number or zero: ! 367: tstl d0 | upper ! 368: bnes 1$ ! 369: tstl d1 | lower ! 370: beqs 3$ |zero ! 371: 1$: addqw #1,d7 ! 372: 2$: subql #1,d7 ! 373: lsll #1,d1 ! 374: roxll #1,d0 | normalize ! 375: btst #20,d0 ! 376: beqs 2$ | loop until normalized ! 377: 3$: rts
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