1*4882a593Smuzhiyun/* SPDX-License-Identifier: GPL-2.0 */ 2*4882a593Smuzhiyun .file "reg_u_add.S" 3*4882a593Smuzhiyun/*---------------------------------------------------------------------------+ 4*4882a593Smuzhiyun | reg_u_add.S | 5*4882a593Smuzhiyun | | 6*4882a593Smuzhiyun | Add two valid (TAG_Valid) FPU_REG numbers, of the same sign, and put the | 7*4882a593Smuzhiyun | result in a destination FPU_REG. | 8*4882a593Smuzhiyun | | 9*4882a593Smuzhiyun | Copyright (C) 1992,1993,1995,1997 | 10*4882a593Smuzhiyun | W. Metzenthen, 22 Parker St, Ormond, Vic 3163, Australia | 11*4882a593Smuzhiyun | E-mail billm@suburbia.net | 12*4882a593Smuzhiyun | | 13*4882a593Smuzhiyun | Call from C as: | 14*4882a593Smuzhiyun | int FPU_u_add(FPU_REG *arg1, FPU_REG *arg2, FPU_REG *answ, | 15*4882a593Smuzhiyun | int control_w) | 16*4882a593Smuzhiyun | Return value is the tag of the answer, or-ed with FPU_Exception if | 17*4882a593Smuzhiyun | one was raised, or -1 on internal error. | 18*4882a593Smuzhiyun | | 19*4882a593Smuzhiyun +---------------------------------------------------------------------------*/ 20*4882a593Smuzhiyun 21*4882a593Smuzhiyun/* 22*4882a593Smuzhiyun | Kernel addition routine FPU_u_add(reg *arg1, reg *arg2, reg *answ). 23*4882a593Smuzhiyun | Takes two valid reg f.p. numbers (TAG_Valid), which are 24*4882a593Smuzhiyun | treated as unsigned numbers, 25*4882a593Smuzhiyun | and returns their sum as a TAG_Valid or TAG_Special f.p. number. 26*4882a593Smuzhiyun | The returned number is normalized. 27*4882a593Smuzhiyun | Basic checks are performed if PARANOID is defined. 28*4882a593Smuzhiyun */ 29*4882a593Smuzhiyun 30*4882a593Smuzhiyun#include "exception.h" 31*4882a593Smuzhiyun#include "fpu_emu.h" 32*4882a593Smuzhiyun#include "control_w.h" 33*4882a593Smuzhiyun 34*4882a593Smuzhiyun.text 35*4882a593SmuzhiyunSYM_FUNC_START(FPU_u_add) 36*4882a593Smuzhiyun pushl %ebp 37*4882a593Smuzhiyun movl %esp,%ebp 38*4882a593Smuzhiyun pushl %esi 39*4882a593Smuzhiyun pushl %edi 40*4882a593Smuzhiyun pushl %ebx 41*4882a593Smuzhiyun 42*4882a593Smuzhiyun movl PARAM1,%esi /* source 1 */ 43*4882a593Smuzhiyun movl PARAM2,%edi /* source 2 */ 44*4882a593Smuzhiyun 45*4882a593Smuzhiyun movl PARAM6,%ecx 46*4882a593Smuzhiyun movl %ecx,%edx 47*4882a593Smuzhiyun subl PARAM7,%ecx /* exp1 - exp2 */ 48*4882a593Smuzhiyun jge L_arg1_larger 49*4882a593Smuzhiyun 50*4882a593Smuzhiyun /* num1 is smaller */ 51*4882a593Smuzhiyun movl SIGL(%esi),%ebx 52*4882a593Smuzhiyun movl SIGH(%esi),%eax 53*4882a593Smuzhiyun 54*4882a593Smuzhiyun movl %edi,%esi 55*4882a593Smuzhiyun movl PARAM7,%edx 56*4882a593Smuzhiyun negw %cx 57*4882a593Smuzhiyun jmp L_accum_loaded 58*4882a593Smuzhiyun 59*4882a593SmuzhiyunL_arg1_larger: 60*4882a593Smuzhiyun /* num1 has larger or equal exponent */ 61*4882a593Smuzhiyun movl SIGL(%edi),%ebx 62*4882a593Smuzhiyun movl SIGH(%edi),%eax 63*4882a593Smuzhiyun 64*4882a593SmuzhiyunL_accum_loaded: 65*4882a593Smuzhiyun movl PARAM3,%edi /* destination */ 66*4882a593Smuzhiyun movw %dx,EXP(%edi) /* Copy exponent to destination */ 67*4882a593Smuzhiyun 68*4882a593Smuzhiyun xorl %edx,%edx /* clear the extension */ 69*4882a593Smuzhiyun 70*4882a593Smuzhiyun#ifdef PARANOID 71*4882a593Smuzhiyun testl $0x80000000,%eax 72*4882a593Smuzhiyun je L_bugged 73*4882a593Smuzhiyun 74*4882a593Smuzhiyun testl $0x80000000,SIGH(%esi) 75*4882a593Smuzhiyun je L_bugged 76*4882a593Smuzhiyun#endif /* PARANOID */ 77*4882a593Smuzhiyun 78*4882a593Smuzhiyun/* The number to be shifted is in %eax:%ebx:%edx */ 79*4882a593Smuzhiyun cmpw $32,%cx /* shrd only works for 0..31 bits */ 80*4882a593Smuzhiyun jnc L_more_than_31 81*4882a593Smuzhiyun 82*4882a593Smuzhiyun/* less than 32 bits */ 83*4882a593Smuzhiyun shrd %cl,%ebx,%edx 84*4882a593Smuzhiyun shrd %cl,%eax,%ebx 85*4882a593Smuzhiyun shr %cl,%eax 86*4882a593Smuzhiyun jmp L_shift_done 87*4882a593Smuzhiyun 88*4882a593SmuzhiyunL_more_than_31: 89*4882a593Smuzhiyun cmpw $64,%cx 90*4882a593Smuzhiyun jnc L_more_than_63 91*4882a593Smuzhiyun 92*4882a593Smuzhiyun subb $32,%cl 93*4882a593Smuzhiyun jz L_exactly_32 94*4882a593Smuzhiyun 95*4882a593Smuzhiyun shrd %cl,%eax,%edx 96*4882a593Smuzhiyun shr %cl,%eax 97*4882a593Smuzhiyun orl %ebx,%ebx 98*4882a593Smuzhiyun jz L_more_31_no_low /* none of the lowest bits is set */ 99*4882a593Smuzhiyun 100*4882a593Smuzhiyun orl $1,%edx /* record the fact in the extension */ 101*4882a593Smuzhiyun 102*4882a593SmuzhiyunL_more_31_no_low: 103*4882a593Smuzhiyun movl %eax,%ebx 104*4882a593Smuzhiyun xorl %eax,%eax 105*4882a593Smuzhiyun jmp L_shift_done 106*4882a593Smuzhiyun 107*4882a593SmuzhiyunL_exactly_32: 108*4882a593Smuzhiyun movl %ebx,%edx 109*4882a593Smuzhiyun movl %eax,%ebx 110*4882a593Smuzhiyun xorl %eax,%eax 111*4882a593Smuzhiyun jmp L_shift_done 112*4882a593Smuzhiyun 113*4882a593SmuzhiyunL_more_than_63: 114*4882a593Smuzhiyun cmpw $65,%cx 115*4882a593Smuzhiyun jnc L_more_than_64 116*4882a593Smuzhiyun 117*4882a593Smuzhiyun movl %eax,%edx 118*4882a593Smuzhiyun orl %ebx,%ebx 119*4882a593Smuzhiyun jz L_more_63_no_low 120*4882a593Smuzhiyun 121*4882a593Smuzhiyun orl $1,%edx 122*4882a593Smuzhiyun jmp L_more_63_no_low 123*4882a593Smuzhiyun 124*4882a593SmuzhiyunL_more_than_64: 125*4882a593Smuzhiyun movl $1,%edx /* The shifted nr always at least one '1' */ 126*4882a593Smuzhiyun 127*4882a593SmuzhiyunL_more_63_no_low: 128*4882a593Smuzhiyun xorl %ebx,%ebx 129*4882a593Smuzhiyun xorl %eax,%eax 130*4882a593Smuzhiyun 131*4882a593SmuzhiyunL_shift_done: 132*4882a593Smuzhiyun /* Now do the addition */ 133*4882a593Smuzhiyun addl SIGL(%esi),%ebx 134*4882a593Smuzhiyun adcl SIGH(%esi),%eax 135*4882a593Smuzhiyun jnc L_round_the_result 136*4882a593Smuzhiyun 137*4882a593Smuzhiyun /* Overflow, adjust the result */ 138*4882a593Smuzhiyun rcrl $1,%eax 139*4882a593Smuzhiyun rcrl $1,%ebx 140*4882a593Smuzhiyun rcrl $1,%edx 141*4882a593Smuzhiyun jnc L_no_bit_lost 142*4882a593Smuzhiyun 143*4882a593Smuzhiyun orl $1,%edx 144*4882a593Smuzhiyun 145*4882a593SmuzhiyunL_no_bit_lost: 146*4882a593Smuzhiyun incw EXP(%edi) 147*4882a593Smuzhiyun 148*4882a593SmuzhiyunL_round_the_result: 149*4882a593Smuzhiyun jmp fpu_reg_round /* Round the result */ 150*4882a593Smuzhiyun 151*4882a593Smuzhiyun 152*4882a593Smuzhiyun 153*4882a593Smuzhiyun#ifdef PARANOID 154*4882a593Smuzhiyun/* If we ever get here then we have problems! */ 155*4882a593SmuzhiyunL_bugged: 156*4882a593Smuzhiyun pushl EX_INTERNAL|0x201 157*4882a593Smuzhiyun call EXCEPTION 158*4882a593Smuzhiyun pop %ebx 159*4882a593Smuzhiyun movl $-1,%eax 160*4882a593Smuzhiyun jmp L_exit 161*4882a593Smuzhiyun 162*4882a593SmuzhiyunL_exit: 163*4882a593Smuzhiyun popl %ebx 164*4882a593Smuzhiyun popl %edi 165*4882a593Smuzhiyun popl %esi 166*4882a593Smuzhiyun leave 167*4882a593Smuzhiyun RET 168*4882a593Smuzhiyun#endif /* PARANOID */ 169*4882a593SmuzhiyunSYM_FUNC_END(FPU_u_add) 170