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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 | .file "reg_u_add.S" /*---------------------------------------------------------------------------+ | reg_u_add.S | | | | Add two valid (TW_Valid) FPU_REG numbers, of the same sign, and put the | | result in a destination FPU_REG. | | | | Copyright (C) 1992,1993 | | W. Metzenthen, 22 Parker St, Ormond, Vic 3163, | | Australia. E-mail billm@vaxc.cc.monash.edu.au | | | | Call from C as: | | void reg_u_add(FPU_REG *arg1, FPU_REG *arg2, FPU_REG *answ, | | int control_w) | | | +---------------------------------------------------------------------------*/ /* | Kernel addition routine reg_u_add(reg *arg1, reg *arg2, reg *answ). | Takes two valid reg f.p. numbers (TW_Valid), which are | treated as unsigned numbers, | and returns their sum as a TW_Valid or TW_S f.p. number. | The returned number is normalized. | Basic checks are performed if PARANOID is defined. */ #include "exception.h" #include "fpu_asm.h" #include "control_w.h" .text .align 2,144 .globl _reg_u_add _reg_u_add: pushl %ebp movl %esp,%ebp pushl %esi pushl %edi pushl %ebx movl PARAM1,%esi /* source 1 */ movl PARAM2,%edi /* source 2 */ #ifdef DENORM_OPERAND cmpl EXP_UNDER,EXP(%esi) jg xOp1_not_denorm call _denormal_operand orl %eax,%eax jnz fpu_Arith_exit xOp1_not_denorm: cmpl EXP_UNDER,EXP(%edi) jg xOp2_not_denorm call _denormal_operand orl %eax,%eax jnz fpu_Arith_exit xOp2_not_denorm: #endif DENORM_OPERAND movl EXP(%esi),%ecx subl EXP(%edi),%ecx /* exp1 - exp2 */ jge L_arg1_larger /* num1 is smaller */ movl SIGL(%esi),%ebx movl SIGH(%esi),%eax movl %edi,%esi negw %cx jmp L_accum_loaded L_arg1_larger: /* num1 has larger or equal exponent */ movl SIGL(%edi),%ebx movl SIGH(%edi),%eax L_accum_loaded: movl PARAM3,%edi /* destination */ /* movb SIGN(%esi),%dl movb %dl,SIGN(%edi) */ /* Copy the sign from the first arg */ movl EXP(%esi),%edx movl %edx,EXP(%edi) /* Copy exponent to destination */ xorl %edx,%edx /* clear the extension */ #ifdef PARANOID testl $0x80000000,%eax je L_bugged testl $0x80000000,SIGH(%esi) je L_bugged #endif PARANOID /* The number to be shifted is in %eax:%ebx:%edx */ cmpw $32,%cx /* shrd only works for 0..31 bits */ jnc L_more_than_31 /* less than 32 bits */ shrd %cl,%ebx,%edx shrd %cl,%eax,%ebx shr %cl,%eax jmp L_shift_done L_more_than_31: cmpw $64,%cx jnc L_more_than_63 subb $32,%cl jz L_exactly_32 shrd %cl,%eax,%edx shr %cl,%eax orl %ebx,%ebx jz L_more_31_no_low /* none of the lowest bits is set */ orl $1,%edx /* record the fact in the extension */ L_more_31_no_low: movl %eax,%ebx xorl %eax,%eax jmp L_shift_done L_exactly_32: movl %ebx,%edx movl %eax,%ebx xorl %eax,%eax jmp L_shift_done L_more_than_63: cmpw $65,%cx jnc L_more_than_64 movl %eax,%edx orl %ebx,%ebx jz L_more_63_no_low orl $1,%edx jmp L_more_63_no_low L_more_than_64: movl $1,%edx /* The shifted nr always at least one '1' */ L_more_63_no_low: xorl %ebx,%ebx xorl %eax,%eax L_shift_done: /* Now do the addition */ addl SIGL(%esi),%ebx adcl SIGH(%esi),%eax jnc L_round_the_result /* Overflow, adjust the result */ rcrl $1,%eax rcrl $1,%ebx rcrl $1,%edx jnc L_no_bit_lost orl $1,%edx L_no_bit_lost: incl EXP(%edi) L_round_the_result: jmp fpu_reg_round /* Round the result */ #ifdef PARANOID /* If we ever get here then we have problems! */ L_bugged: pushl EX_INTERNAL|0x201 call EXCEPTION pop %ebx jmp L_exit #endif PARANOID L_exit: popl %ebx popl %edi popl %esi leave ret |