Orange Pi5 kernel

^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   1) // SPDX-License-Identifier: GPL-2.0
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   2) /*---------------------------------------------------------------------------+
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   3)  |  reg_divide.c                                                             |
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   4)  |                                                                           |
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   5)  | Divide one FPU_REG by another and put the result in a destination FPU_REG.|
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   6)  |                                                                           |
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   7)  | Copyright (C) 1996                                                        |
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   8)  |                  W. Metzenthen, 22 Parker St, Ormond, Vic 3163, Australia |
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   9)  |                  E-mail   billm@jacobi.maths.monash.edu.au                |
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  10)  |                                                                           |
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  11)  |    Return value is the tag of the answer, or-ed with FPU_Exception if     |
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  12)  |    one was raised, or -1 on internal error.                               |
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  13)  |                                                                           |
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  14)  +---------------------------------------------------------------------------*/
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  15) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  16) /*---------------------------------------------------------------------------+
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  17)  | The destination may be any FPU_REG, including one of the source FPU_REGs. |
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  18)  +---------------------------------------------------------------------------*/
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  19) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  20) #include "exception.h"
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  21) #include "reg_constant.h"
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  22) #include "fpu_emu.h"
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  23) #include "fpu_system.h"
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  24) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  25) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  26)   Divide one register by another and put the result into a third register.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  27)   */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  28) int FPU_div(int flags, int rm, int control_w)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  29) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  30) 	FPU_REG x, y;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  31) 	FPU_REG const *a, *b, *st0_ptr, *st_ptr;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  32) 	FPU_REG *dest;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  33) 	u_char taga, tagb, signa, signb, sign, saved_sign;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  34) 	int tag, deststnr;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  35) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  36) 	if (flags & DEST_RM)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  37) 		deststnr = rm;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  38) 	else
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  39) 		deststnr = 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  40) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  41) 	if (flags & REV) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  42) 		b = &st(0);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  43) 		st0_ptr = b;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  44) 		tagb = FPU_gettag0();
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  45) 		if (flags & LOADED) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  46) 			a = (FPU_REG *) rm;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  47) 			taga = flags & 0x0f;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  48) 		} else {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  49) 			a = &st(rm);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  50) 			st_ptr = a;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  51) 			taga = FPU_gettagi(rm);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  52) 		}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  53) 	} else {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  54) 		a = &st(0);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  55) 		st0_ptr = a;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  56) 		taga = FPU_gettag0();
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  57) 		if (flags & LOADED) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  58) 			b = (FPU_REG *) rm;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  59) 			tagb = flags & 0x0f;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  60) 		} else {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  61) 			b = &st(rm);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  62) 			st_ptr = b;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  63) 			tagb = FPU_gettagi(rm);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  64) 		}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  65) 	}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  66) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  67) 	signa = getsign(a);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  68) 	signb = getsign(b);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  69) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  70) 	sign = signa ^ signb;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  71) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  72) 	dest = &st(deststnr);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  73) 	saved_sign = getsign(dest);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  74) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  75) 	if (!(taga | tagb)) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  76) 		/* Both regs Valid, this should be the most common case. */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  77) 		reg_copy(a, &x);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  78) 		reg_copy(b, &y);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  79) 		setpositive(&x);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  80) 		setpositive(&y);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  81) 		tag = FPU_u_div(&x, &y, dest, control_w, sign);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  82) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  83) 		if (tag < 0)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  84) 			return tag;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  85) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  86) 		FPU_settagi(deststnr, tag);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  87) 		return tag;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  88) 	}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  89) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  90) 	if (taga == TAG_Special)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  91) 		taga = FPU_Special(a);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  92) 	if (tagb == TAG_Special)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  93) 		tagb = FPU_Special(b);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  94) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  95) 	if (((taga == TAG_Valid) && (tagb == TW_Denormal))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  96) 	    || ((taga == TW_Denormal) && (tagb == TAG_Valid))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  97) 	    || ((taga == TW_Denormal) && (tagb == TW_Denormal))) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  98) 		if (denormal_operand() < 0)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  99) 			return FPU_Exception;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 100) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 101) 		FPU_to_exp16(a, &x);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 102) 		FPU_to_exp16(b, &y);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 103) 		tag = FPU_u_div(&x, &y, dest, control_w, sign);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 104) 		if (tag < 0)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 105) 			return tag;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 106) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 107) 		FPU_settagi(deststnr, tag);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 108) 		return tag;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 109) 	} else if ((taga <= TW_Denormal) && (tagb <= TW_Denormal)) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 110) 		if (tagb != TAG_Zero) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 111) 			/* Want to find Zero/Valid */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 112) 			if (tagb == TW_Denormal) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 113) 				if (denormal_operand() < 0)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 114) 					return FPU_Exception;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 115) 			}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 116) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 117) 			/* The result is zero. */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 118) 			FPU_copy_to_regi(&CONST_Z, TAG_Zero, deststnr);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 119) 			setsign(dest, sign);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 120) 			return TAG_Zero;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 121) 		}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 122) 		/* We have an exception condition, either 0/0 or Valid/Zero. */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 123) 		if (taga == TAG_Zero) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 124) 			/* 0/0 */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 125) 			return arith_invalid(deststnr);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 126) 		}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 127) 		/* Valid/Zero */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 128) 		return FPU_divide_by_zero(deststnr, sign);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 129) 	}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 130) 	/* Must have infinities, NaNs, etc */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 131) 	else if ((taga == TW_NaN) || (tagb == TW_NaN)) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 132) 		if (flags & LOADED)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 133) 			return real_2op_NaN((FPU_REG *) rm, flags & 0x0f, 0,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 134) 					    st0_ptr);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 135) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 136) 		if (flags & DEST_RM) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 137) 			int tag;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 138) 			tag = FPU_gettag0();
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 139) 			if (tag == TAG_Special)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 140) 				tag = FPU_Special(st0_ptr);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 141) 			return real_2op_NaN(st0_ptr, tag, rm,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 142) 					    (flags & REV) ? st0_ptr : &st(rm));
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 143) 		} else {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 144) 			int tag;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 145) 			tag = FPU_gettagi(rm);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 146) 			if (tag == TAG_Special)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 147) 				tag = FPU_Special(&st(rm));
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 148) 			return real_2op_NaN(&st(rm), tag, 0,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 149) 					    (flags & REV) ? st0_ptr : &st(rm));
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 150) 		}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 151) 	} else if (taga == TW_Infinity) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 152) 		if (tagb == TW_Infinity) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 153) 			/* infinity/infinity */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 154) 			return arith_invalid(deststnr);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 155) 		} else {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 156) 			/* tagb must be Valid or Zero */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 157) 			if ((tagb == TW_Denormal) && (denormal_operand() < 0))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 158) 				return FPU_Exception;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 159) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 160) 			/* Infinity divided by Zero or Valid does
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 161) 			   not raise and exception, but returns Infinity */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 162) 			FPU_copy_to_regi(a, TAG_Special, deststnr);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 163) 			setsign(dest, sign);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 164) 			return taga;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 165) 		}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 166) 	} else if (tagb == TW_Infinity) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 167) 		if ((taga == TW_Denormal) && (denormal_operand() < 0))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 168) 			return FPU_Exception;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 169) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 170) 		/* The result is zero. */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 171) 		FPU_copy_to_regi(&CONST_Z, TAG_Zero, deststnr);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 172) 		setsign(dest, sign);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 173) 		return TAG_Zero;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 174) 	}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 175) #ifdef PARANOID
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 176) 	else {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 177) 		EXCEPTION(EX_INTERNAL | 0x102);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 178) 		return FPU_Exception;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 179) 	}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 180) #endif /* PARANOID */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 181) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 182) 	return 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 183) }