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 /* * Copyright (C) 2000 Hewlett-Packard Co * Copyright (C) 2000 David Mosberger-Tang * * 32-bit integer division. * * This code is based on the application note entitled "Divide, Square Root * and Remainder Algorithms for the IA-64 Architecture". This document * is available as Intel document number 248725-002 or via the web at * http://developer.intel.com/software/opensource/numerics/ * * For more details on the theory behind these algorithms, see "IA-64 * and Elementary Functions" by Peter Markstein; HP Professional Books * (http://www.goodreads.com/book/show/2019887.Ia_64_and_Elementary_Functions) */ #include #ifdef MODULO # define OP mod #else # define OP div #endif #ifdef UNSIGNED # define SGN u # define EXTEND zxt4 # define INT_TO_FP(a,b) fcvt.xuf.s1 a=b # define FP_TO_INT(a,b) fcvt.fxu.trunc.s1 a=b #else # define SGN # define EXTEND sxt4 # define INT_TO_FP(a,b) fcvt.xf a=b # define FP_TO_INT(a,b) fcvt.fx.trunc.s1 a=b #endif #define PASTE1(a,b) a##b #define PASTE(a,b) PASTE1(a,b) #define NAME PASTE(PASTE(__,SGN),PASTE(OP,si3)) GLOBAL_ENTRY(NAME) .regstk 2,0,0,0 // Transfer inputs to FP registers. mov r2 = 0xffdd // r2 = -34 + 65535 (fp reg format bias) EXTEND in0 = in0 // in0 = a EXTEND in1 = in1 // in1 = b ;; setf.sig f8 = in0 setf.sig f9 = in1 #ifdef MODULO sub in1 = r0, in1 // in1 = -b #endif ;; // Convert the inputs to FP, to avoid FP software-assist faults. INT_TO_FP(f8, f8) INT_TO_FP(f9, f9) ;; setf.exp f7 = r2 // f7 = 2^-34 frcpa.s1 f6, p6 = f8, f9 // y0 = frcpa(b) ;; (p6) fmpy.s1 f8 = f8, f6 // q0 = a*y0 (p6) fnma.s1 f6 = f9, f6, f1 // e0 = -b*y0 + 1 ;; #ifdef MODULO setf.sig f9 = in1 // f9 = -b #endif (p6) fma.s1 f8 = f6, f8, f8 // q1 = e0*q0 + q0 (p6) fma.s1 f6 = f6, f6, f7 // e1 = e0*e0 + 2^-34 ;; #ifdef MODULO setf.sig f7 = in0 #endif (p6) fma.s1 f6 = f6, f8, f8 // q2 = e1*q1 + q1 ;; FP_TO_INT(f6, f6) // q = trunc(q2) ;; #ifdef MODULO xma.l f6 = f6, f9, f7 // r = q*(-b) + a ;; #endif getf.sig r8 = f6 // transfer result to result register br.ret.sptk.many rp END(NAME)