1 // SPDX-License-Identifier: GPL-2.0-or-later
3  * Linux/PA-RISC Project (http://www.parisc-linux.org/)
5  * Floating-point emulation code
6  *  Copyright (C) 2001 Hewlett-Packard (Paul Bame) <bame@debian.org>
42     register unsigned int left, right, result, extent;  in sgl_fadd()  local
52     left = *leftptr;  in sgl_fadd()
57     Sgl_xortointp1(left,right,/*to*/save);  in sgl_fadd()
62     if ((result_exponent = Sgl_exponent(left)) == SGL_INFINITY_EXPONENT)  in sgl_fadd()
64 	if (Sgl_iszero_mantissa(left))   in sgl_fadd()
82 		*dstptr = left;  in sgl_fadd()
91             if (Sgl_isone_signaling(left))   in sgl_fadd()
97         	Sgl_set_quiet(left);  in sgl_fadd()
115  	    *dstptr = left;  in sgl_fadd()
118 	} /* End left NaN or Infinity processing */  in sgl_fadd()
151     Sgl_copytoint_exponentmantissa(left,signless_upper_left);  in sgl_fadd()
157 	/* Set the left operand to the larger one by XOR swap *  in sgl_fadd()
160 	Sgl_xorfromintp1(save,left,/*to*/left);  in sgl_fadd()
161 	result_exponent = Sgl_exponent(left);  in sgl_fadd()
163     /* Invariant:  left is not smaller than right. */   in sgl_fadd()
171 	    if(Sgl_iszero_exponentmantissa(left))  in sgl_fadd()
176 		    Sgl_or_signs(left,/*with*/right);  in sgl_fadd()
180 		    Sgl_and_signs(left,/*with*/right);  in sgl_fadd()
185 		/* Left is not a zero and must be the result.  Trapped  in sgl_fadd()
186 		 * underflows are signaled if left is denormalized.  Result  in sgl_fadd()
191 	    	    sign_save = Sgl_signextendedsign(left);  in sgl_fadd()
192 		    Sgl_leftshiftby1(left);  in sgl_fadd()
193 		    Sgl_normalize(left,result_exponent);  in sgl_fadd()
194 		    Sgl_set_sign(left,/*using*/sign_save);  in sgl_fadd()
195 		    Sgl_setwrapped_exponent(left,result_exponent,unfl);  in sgl_fadd()
196 		    *dstptr = left;  in sgl_fadd()
200 	    *dstptr = left;  in sgl_fadd()
213 		Sgl_subtract(left,/*minus*/right,/*into*/result);  in sgl_fadd()
230 		Sgl_addition(left,right,/*into*/result);  in sgl_fadd()
258     Sgl_clear_exponent_set_hidden(left);  in sgl_fadd()
259     diff_exponent = result_exponent - right_exponent;  in sgl_fadd()
284 	Sgl_subtract_withextension(left,/*minus*/right,/*with*/extent,/*into*/result);  in sgl_fadd()
288 	    /* A straightforward algorithm would now shift the result  in sgl_fadd()
289 	     * and extension left until the hidden bit becomes one.  Not  in sgl_fadd()
290 	     * all of the extension bits need participate in the shift.  in sgl_fadd()
292 	     * needed.  If only a single shift is needed then the guard  in sgl_fadd()
295 	     * shift is needed, then all bits to the right of the guard   in sgl_fadd()
305 		/* Must have been "x-x" or "x+(-x)". */  in sgl_fadd()
311 	    result_exponent--;  in sgl_fadd()
317 		    /* Denormalized, exponent should be zero.  Left operand *  in sgl_fadd()
330 	    /* Check for denormalized, exponent should be zero.  Left    *   in sgl_fadd()
335 	    /* Shift extension to complete one bit of normalization and  in sgl_fadd()
339 	    /* Discover first one bit to determine shift amount.  Use a  in sgl_fadd()
347 		if((result_exponent -= 8) <= 0  && !underflowtrap)  in sgl_fadd()
355 		if((result_exponent -= 4) <= 0 && !underflowtrap)  in sgl_fadd()
359 	     * otherwise select the proper shift. */  in sgl_fadd()
375 		    result_exponent -= 3;  in sgl_fadd()
382 		    result_exponent -= 2;  in sgl_fadd()
391 		    result_exponent -= 1;  in sgl_fadd()
415 	    Sgl_right_align(result,/*by*/(1-result_exponent),extent);  in sgl_fadd()
426 	Sgl_addition(left,right,/*to*/result);  in sgl_fadd()
439      * all zeros so no shift is needed. */  in sgl_fadd()