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1.1 ! root 1: .data ! 2: .asciz "@(#)Fadds.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: * ieee single floating run-time support ! 12: * copyright 1981, Richard E. James III ! 13: * translated to SUN idiom 14 March 1983 rt ! 14: */ ! 15: ! 16: /* single floating addition and subtraction */ ! 17: /* ! 18: * entry conditions: ! 19: * first argument in d0 ! 20: * second argument in d1 ! 21: * exit conditions: ! 22: * result (4 bytes) in d0 ! 23: * ! 24: * register conventions: ! 25: * d0 operand 1 ! 26: * d1 operand 2/sum ! 27: * d2 sign of operand 1 ! 28: * d3 sign of operand 2 ! 29: * d4 exponent of operand 1 ! 30: * d5 exponent of operand 2 ! 31: * d6 difference of exponents ! 32: * d7 reserved for sticky ! 33: */ ! 34: SAVEMASK = 0x3f00 | registers d2-d7 ! 35: RESTMASK = 0xfc ! 36: NSAVED = 6*4 | 6 registers * sizeof(register) ! 37: ! 38: RTENTRY(Fsubs) ! 39: bchg #31,d1 ! 40: jra adding ! 41: RTENTRY(Fadds) ! 42: adding: ! 43: | save registers and load operands into registers ! 44: moveml #SAVEMASK,sp@- | registers d2-d7 ! 45: | extract signs ! 46: asll #1,d0 | sign ->c ! 47: scs d2 | c -> d4 ! 48: asll #1,d1 ! 49: scs d3 ! 50: | compare and exchange to put larger in d0 ! 51: cmpl d1,d0 ! 52: blss 1$ ! 53: exg d0,d1 ! 54: exg d2,d3 ! 55: | extract exponents ! 56: 1$: roll #8,d1 ! 57: roll #8,d0 ! 58: clrl d5 ! 59: movb d1,d5 | larger exp ! 60: clrw d4 ! 61: movb d0,d4 | smaller exp ! 62: bnes 3$ | not zero or denormalized ! 63: | smaller is 0 or is denormalized ! 64: tstl d0 | if smaller == 0 ! 65: jeq signofzero | then use larger (sign of 0-0 unpredictable) ! 66: tstb d5 | larger exponent ! 67: bnes 4$ | not gu ! 68: | both are denormalized ! 69: cmpb d3,d2 | compare signs ! 70: bnes 2$ ! 71: addl d0,d1 ! 72: addxb d1,d1 | incr exp to 1 if overflow ! 73: jra asbuild ! 74: 2$: subl d0,d1 | subtract ! 75: jne asbuild ! 76: jra cancel ! 77: | neither is denormalized ! 78: 3$: movb #1,d0 | clear exp and ! 79: rorl #1,d0 ! 80: 4$: movb #1,d1 | ... clr hidden bit ! 81: rorl #1,d1 ! 82: cmpb #0xff,d5 ! 83: jeq ovfl | inf or nan ! 84: | align smaller ! 85: movw d5,d6 ! 86: subw d4,d6 | difference of exponents ! 87: cmpw #16,d6 ! 88: bges bigshift | Branch if shift 26 or more places. ! 89: check8: cmpw #8,d6 ! 90: blts shortshift | exit when <8 *s ! 91: tstb d0 ! 92: beqs shift8 | Branch if no bits to be lost. ! 93: bset #8,d0 | Sticky bit on. ! 94: shift8: ! 95: subqw #8,d6 ! 96: lsrl #8,d0 | align ! 97: bra check8 | loop ! 98: bigshift: ! 99: cmpw #26,d6 ! 100: bges greatshift | Branch if only sticky left. ! 101: tstw d0 ! 102: beqs 1$ ! 103: bset #16,d0 | Set sticky bit. ! 104: 1$: ! 105: clrw d0 ! 106: swap d0 ! 107: subw #16,d6 ! 108: bras check8 ! 109: greatshift: ! 110: moveq #1,d0 | Here's a sticky bit. ! 111: bras addorsub ! 112: shortshift: ! 113: movb d0,d7 ! 114: lsrl d6,d0 | finish align ! 115: cmpw #2,d6 ! 116: bges stickit | Branch if shift >=2 so whole byte sticky. ! 117: andb #1,d7 | Shift = 0 or 1 so only lsb sticks. ! 118: stickit: ! 119: tstb d7 ! 120: beqs addorsub | Branch if no bits to stick. ! 121: bset #0,d0 | Set a sticky bit on. ! 122: addorsub: ! 123: cmpb d3,d2 | cmp signs ! 124: bnes diff | decide whether to add or subtract ! 125: ! 126: | add them ! 127: addl d0,d1 | sum ! 128: bccs endas | no carry here ! 129: roxrl #1,d1 | pull in overflow *s ! 130: addqw #1,d5 ! 131: cmpw #0xff,d5 ! 132: blts endas | no ofl ! 133: bras a_geninf ! 134: ! 135: ! 136: signofzero: | Set proper sign of zero. ! 137: cmpb d2,d3 ! 138: beqs usel | If signs are equal, use d3. ! 139: tstl d1 ! 140: bnes usel | Branch if not zero. ! 141: clrb d3 | Sign if positive otherwise. ! 142: bras usel ! 143: ! 144: | subtract them ! 145: diff: subl d0,d1 ! 146: bmis endas | if normalized ! 147: beqs cancel | result == 0 ! 148: 9$: asll #1,d1 | normalize ! 149: dbmi d5,9$ | dec exponent ! 150: subqw #1,d5 ! 151: bgts endas | not gu ! 152: beqs 10$ ! 153: clrw d5 ! 154: lsrl #1,d1 | grad und ! 155: 10$: lsrl #1,d1 ! 156: ! 157: endas: | round (NOT FULLY STANDARD) ! 158: addl #0x80,d1 | round ! 159: bccs testeven | round did not cause mantissa to ofl ! 160: roxrl #1,d1 ! 161: addqw #1,d5 ! 162: cmpw #0xff,d5 ! 163: beqs a_geninf | round caused exp to overflow ! 164: bras rebuild ! 165: testeven: | Test if ambiguous case. ! 166: tstb d1 ! 167: bnes rebuild | Branch if not ambiguous. ! 168: bclr #8,d1 | Force round to even. ! 169: rebuild: | rebuild answer ! 170: lsll #1,d1 | toss hidden ! 171: usel: movb d5,d1 | insert exponent ! 172: asbuild:rorl #8,d1 ! 173: roxrb #1,d3 ! 174: roxrl #1,d1 | apply sign ! 175: | d1 now has answer ! 176: movl d1,d0 ! 177: asexit: ! 178: moveml sp@+,#RESTMASK ! 179: RET ! 180: ! 181: | EXCEPTION CASES ! 182: ovfl: | largest exponent = 255 ! 183: lsll #1,d1 ! 184: tstl d1 | larger mantissa ! 185: bnes usel | larger == nan ! 186: cmpb d4,d5 | exps ! 187: bnes usel | larger == inf ! 188: | AFFINE MODE ASSUMED IN THIS IMPLEMENTATION ! 189: cmpb d3,d2 | signs ! 190: beqs usel | inf+inf = inf ! 191: |gennan: ! 192: movl #0x7f800001,d0 ! 193: bras asexit ! 194: ! 195: | complete cancellation ! 196: cancel: clrl d0 | result == 0 ! 197: | need minus 0 for (-0)+(-0), round to -inf ! 198: bras asexit ! 199: | result overflows: ! 200: a_geninf:movl #0xff,d1 ! 201: bras asbuild ! 202: ! 203: ! 204: /* ! 205: * ieee single floating compare ! 206: * copyright 1981, Richard E. James III ! 207: * translated to SUN idiom 29 March 1983 rt ! 208: */ ! 209: ! 210: /* ! 211: * entry conditions: ! 212: * first argument in d0 ! 213: * second argument in d1 ! 214: * exit conditions: ! 215: * result in condition code ! 216: * d0/d1 trashed ! 217: * ! 218: * register conventions: ! 219: * d0 operand 1 ! 220: * d1 operand 2 ! 221: * d2 scratch ! 222: */ ! 223: NSAVED = 4 ! 224: CODE = NSAVED ! 225: ! 226: RTENTRY(Fcmps) ! 227: #ifdef PROF ! 228: unlk a6 | don't get in the way of the cc. ! 229: #endif ! 230: subqw #2,sp | save space for condition code return ! 231: movl d2,sp@- | save register ! 232: ! 233: movl d1,d2 ! 234: andl d0,d2 | compare signs ! 235: bpls 1$ ! 236: exg d0,d1 | both minus ! 237: 1$: cmpl d1,d0 | main compare ! 238: bgts 1f ! 239: blts 2f ! 240: movw #FEQ,sp@(CODE) ! 241: bras 3f ! 242: 1: ! 243: movw #FGT,sp@(CODE) ! 244: bras 3f ! 245: 2: ! 246: movw #FLT,sp@(CODE) ! 247: 3: ! 248: lsll #1,d0 ! 249: lsll #1,d1 ! 250: cmpl d1,d0 ! 251: bccs 2$ ! 252: exg d0,d1 | find larger ! 253: 2$: cmpl #0xff000000,d0 ! 254: blss 3$ ! 255: | nan ! 256: movw #FUN,sp@(CODE) | c for unordered ! 257: 3$: tstl d0 ! 258: bnes 4$ ! 259: movw #FEQ,sp@(CODE) | -0 == 0 ! 260: | result is in sp@(CODE) ! 261: 4$: | restore saved register and go ! 262: movl sp@+,d2 ! 263: rtr
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