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1 | /* Copyright (C) 1996-2019 Free Software Foundation, Inc. |
---|---|

2 | This file is part of the GNU C Library. |

3 | Contributed by Richard Henderson <rth@tamu.edu>. |

4 | |

5 | The GNU C Library is free software; you can redistribute it and/or |

6 | modify it under the terms of the GNU Lesser General Public |

7 | License as published by the Free Software Foundation; either |

8 | version 2.1 of the License, or (at your option) any later version. |

9 | |

10 | The GNU C Library is distributed in the hope that it will be useful, |

11 | but WITHOUT ANY WARRANTY; without even the implied warranty of |

12 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |

13 | Lesser General Public License for more details. |

14 | |

15 | You should have received a copy of the GNU Lesser General Public |

16 | License along with the GNU C Library. If not, see |

17 | <http://www.gnu.org/licenses/>. */ |

18 | |

19 | #include "div_libc.h" |

20 | |

21 | #undef FRAME |

22 | #ifdef __alpha_fix__ |

23 | #define FRAME 0 |

24 | #else |

25 | #define FRAME 16 |

26 | #endif |

27 | |

28 | #undef X |

29 | #undef Y |

30 | #define X $17 |

31 | #define Y $18 |

32 | |

33 | .set noat |

34 | |

35 | .align 4 |

36 | .globl ldiv |

37 | .ent ldiv |

38 | ldiv: |

39 | .frame sp, FRAME, ra |

40 | #if FRAME > 0 |

41 | lda sp, -FRAME(sp) |

42 | #endif |

43 | #ifdef PROF |

44 | .set macro |

45 | ldgp gp, 0(pv) |

46 | lda AT, _mcount |

47 | jsr AT, (AT), _mcount |

48 | .set nomacro |

49 | .prologue 1 |

50 | #else |

51 | .prologue 0 |

52 | #endif |

53 | |

54 | beq Y, $divbyzero |

55 | excb |

56 | mf_fpcr $f10 |

57 | |

58 | _ITOFT2 X, $f0, 0, Y, $f1, 8 |

59 | |

60 | .align 4 |

61 | cvtqt $f0, $f0 |

62 | cvtqt $f1, $f1 |

63 | divt/c $f0, $f1, $f0 |

64 | unop |

65 | |

66 | /* Check to see if X fit in the double as an exact value. */ |

67 | sll X, (64-53), AT |

68 | sra AT, (64-53), AT |

69 | cmpeq X, AT, AT |

70 | beq AT, $x_big |

71 | |

72 | /* If we get here, we're expecting exact results from the division. |

73 | Do nothing else besides convert and clean up. */ |

74 | cvttq/c $f0, $f0 |

75 | excb |

76 | mt_fpcr $f10 |

77 | _FTOIT $f0, $0, 0 |

78 | |

79 | $egress: |

80 | mulq $0, Y, $1 |

81 | subq X, $1, $1 |

82 | |

83 | stq $0, 0($16) |

84 | stq $1, 8($16) |

85 | mov $16, $0 |

86 | |

87 | #if FRAME > 0 |

88 | lda sp, FRAME(sp) |

89 | #endif |

90 | ret |

91 | |

92 | .align 4 |

93 | $x_big: |

94 | /* If we get here, X is large enough that we don't expect exact |

95 | results, and neither X nor Y got mis-translated for the fp |

96 | division. Our task is to take the fp result, figure out how |

97 | far it's off from the correct result and compute a fixup. */ |

98 | |

99 | #define Q v0 /* quotient */ |

100 | #define R t0 /* remainder */ |

101 | #define SY t1 /* scaled Y */ |

102 | #define S t2 /* scalar */ |

103 | #define QY t3 /* Q*Y */ |

104 | |

105 | /* The fixup code below can only handle unsigned values. */ |

106 | or X, Y, AT |

107 | mov $31, t5 |

108 | blt AT, $fix_sign_in |

109 | $fix_sign_in_ret1: |

110 | cvttq/c $f0, $f0 |

111 | |

112 | _FTOIT $f0, Q, 8 |

113 | $fix_sign_in_ret2: |

114 | mulq Q, Y, QY |

115 | excb |

116 | mt_fpcr $f10 |

117 | |

118 | .align 4 |

119 | subq QY, X, R |

120 | mov Y, SY |

121 | mov 1, S |

122 | bgt R, $q_high |

123 | |

124 | $q_high_ret: |

125 | subq X, QY, R |

126 | mov Y, SY |

127 | mov 1, S |

128 | bgt R, $q_low |

129 | |

130 | $q_low_ret: |

131 | negq Q, t4 |

132 | cmovlbs t5, t4, Q |

133 | br $egress |

134 | |

135 | .align 4 |

136 | /* The quotient that we computed was too large. We need to reduce |

137 | it by S such that Y*S >= R. Obviously the closer we get to the |

138 | correct value the better, but overshooting high is ok, as we'll |

139 | fix that up later. */ |

140 | 0: |

141 | addq SY, SY, SY |

142 | addq S, S, S |

143 | $q_high: |

144 | cmpult SY, R, AT |

145 | bne AT, 0b |

146 | |

147 | subq Q, S, Q |

148 | unop |

149 | subq QY, SY, QY |

150 | br $q_high_ret |

151 | |

152 | .align 4 |

153 | /* The quotient that we computed was too small. Divide Y by the |

154 | current remainder (R) and add that to the existing quotient (Q). |

155 | The expectation, of course, is that R is much smaller than X. */ |

156 | /* Begin with a shift-up loop. Compute S such that Y*S >= R. We |

157 | already have a copy of Y in SY and the value 1 in S. */ |

158 | 0: |

159 | addq SY, SY, SY |

160 | addq S, S, S |

161 | $q_low: |

162 | cmpult SY, R, AT |

163 | bne AT, 0b |

164 | |

165 | /* Shift-down and subtract loop. Each iteration compares our scaled |

166 | Y (SY) with the remainder (R); if SY <= R then X is divisible by |

167 | Y's scalar (S) so add it to the quotient (Q). */ |

168 | 2: addq Q, S, t3 |

169 | srl S, 1, S |

170 | cmpule SY, R, AT |

171 | subq R, SY, t4 |

172 | |

173 | cmovne AT, t3, Q |

174 | cmovne AT, t4, R |

175 | srl SY, 1, SY |

176 | bne S, 2b |

177 | |

178 | br $q_low_ret |

179 | |

180 | .align 4 |

181 | $fix_sign_in: |

182 | /* If we got here, then X|Y is negative. Need to adjust everything |

183 | such that we're doing unsigned division in the fixup loop. */ |

184 | /* T5 is true if result should be negative. */ |

185 | xor X, Y, AT |

186 | cmplt AT, 0, t5 |

187 | cmplt X, 0, AT |

188 | negq X, t0 |

189 | |

190 | cmovne AT, t0, X |

191 | cmplt Y, 0, AT |

192 | negq Y, t0 |

193 | |

194 | cmovne AT, t0, Y |

195 | blbc t5, $fix_sign_in_ret1 |

196 | |

197 | cvttq/c $f0, $f0 |

198 | _FTOIT $f0, Q, 8 |

199 | .align 3 |

200 | negq Q, Q |

201 | br $fix_sign_in_ret2 |

202 | |

203 | $divbyzero: |

204 | mov a0, v0 |

205 | lda a0, GEN_INTDIV |

206 | call_pal PAL_gentrap |

207 | stq zero, 0(v0) |

208 | stq zero, 8(v0) |

209 | |

210 | #if FRAME > 0 |

211 | lda sp, FRAME(sp) |

212 | #endif |

213 | ret |

214 | |

215 | .end ldiv |

216 | |

217 | weak_alias (ldiv, lldiv) |

218 | weak_alias (ldiv, imaxdiv) |

219 |

Warning: That file was not part of the compilation database. It may have many parsing errors.