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212 lines
5.0 KiB
ArmAsm
212 lines
5.0 KiB
ArmAsm
/* libgcc functions for Blackfin.
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Copyright (C) 2005-2016 Free Software Foundation, Inc.
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Contributed by Analog Devices.
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This file is part of GCC.
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GCC is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 3, or (at your option)
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any later version.
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GCC is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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Under Section 7 of GPL version 3, you are granted additional
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permissions described in the GCC Runtime Library Exception, version
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3.1, as published by the Free Software Foundation.
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You should have received a copy of the GNU General Public License and
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a copy of the GCC Runtime Library Exception along with this program;
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see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
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<http://www.gnu.org/licenses/>. */
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#ifdef L_divsi3
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.text
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.align 2
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.global ___divsi3;
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.type ___divsi3, STT_FUNC;
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___divsi3:
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[--SP]= RETS;
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[--SP] = R7;
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R2 = -R0;
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CC = R0 < 0;
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IF CC R0 = R2;
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R7 = CC;
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R2 = -R1;
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CC = R1 < 0;
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IF CC R1 = R2;
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R2 = CC;
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R7 = R7 ^ R2;
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CALL ___udivsi3;
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CC = R7;
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R1 = -R0;
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IF CC R0 = R1;
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R7 = [SP++];
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RETS = [SP++];
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RTS;
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#endif
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#ifdef L_modsi3
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.align 2
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.global ___modsi3;
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.type ___modsi3, STT_FUNC;
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___modsi3:
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[--SP] = RETS;
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[--SP] = R0;
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[--SP] = R1;
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CALL ___divsi3;
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R2 = [SP++];
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R1 = [SP++];
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R2 *= R0;
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R0 = R1 - R2;
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RETS = [SP++];
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RTS;
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#endif
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#ifdef L_udivsi3
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.align 2
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.global ___udivsi3;
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.type ___udivsi3, STT_FUNC;
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___udivsi3:
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P0 = 32;
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LSETUP (0f, 1f) LC0 = P0;
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/* upper half of dividend */
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R3 = 0;
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0:
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/* The first time round in the loop we shift in garbage, but since we
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perform 33 shifts, it doesn't matter. */
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R0 = ROT R0 BY 1;
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R3 = ROT R3 BY 1;
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R2 = R3 - R1;
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CC = R3 < R1 (IU);
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1:
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/* Last instruction of the loop. */
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IF ! CC R3 = R2;
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/* Shift in the last bit. */
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R0 = ROT R0 BY 1;
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/* R0 is the result, R3 contains the remainder. */
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R0 = ~ R0;
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RTS;
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#endif
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#ifdef L_umodsi3
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.align 2
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.global ___umodsi3;
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.type ___umodsi3, STT_FUNC;
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___umodsi3:
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[--SP] = RETS;
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CALL ___udivsi3;
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R0 = R3;
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RETS = [SP++];
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RTS;
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#endif
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#ifdef L_umulsi3_highpart
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.align 2
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.global ___umulsi3_highpart;
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.type ___umulsi3_highpart, STT_FUNC;
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___umulsi3_highpart:
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A1 = R1.L * R0.L (FU);
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A1 = A1 >> 16;
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A0 = R1.H * R0.H, A1 += R1.L * R0.H (FU);
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A1 += R0.L * R1.H (FU);
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A1 = A1 >> 16;
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A0 += A1;
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R0 = A0 (FU);
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RTS;
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#endif
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#ifdef L_smulsi3_highpart
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.align 2
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.global ___smulsi3_highpart;
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.type ___smulsi3_highpart, STT_FUNC;
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___smulsi3_highpart:
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A1 = R1.L * R0.L (FU);
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A1 = A1 >> 16;
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A0 = R0.H * R1.H, A1 += R0.H * R1.L (IS,M);
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A1 += R1.H * R0.L (IS,M);
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A1 = A1 >>> 16;
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R0 = (A0 += A1);
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RTS;
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#endif
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#ifdef L_muldi3
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.align 2
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.global ___muldi3;
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.type ___muldi3, STT_FUNC;
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/*
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R1:R0 * R3:R2
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= R1.h:R1.l:R0.h:R0.l * R3.h:R3.l:R2.h:R2.l
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[X] = (R1.h * R3.h) * 2^96
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[X] + (R1.h * R3.l + R1.l * R3.h) * 2^80
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[X] + (R1.h * R2.h + R1.l * R3.l + R3.h * R0.h) * 2^64
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[T1] + (R1.h * R2.l + R3.h * R0.l + R1.l * R2.h + R3.l * R0.h) * 2^48
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[T2] + (R1.l * R2.l + R3.l * R0.l + R0.h * R2.h) * 2^32
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[T3] + (R0.l * R2.h + R2.l * R0.h) * 2^16
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[T4] + (R0.l * R2.l)
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We can discard the first three lines marked "X" since we produce
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only a 64 bit result. So, we need ten 16-bit multiplies.
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Individual mul-acc results:
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[E1] = R1.h * R2.l + R3.h * R0.l + R1.l * R2.h + R3.l * R0.h
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[E2] = R1.l * R2.l + R3.l * R0.l + R0.h * R2.h
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[E3] = R0.l * R2.h + R2.l * R0.h
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[E4] = R0.l * R2.l
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We also need to add high parts from lower-level results to higher ones:
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E[n]c = E[n] + (E[n+1]c >> 16), where E4c := E4
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One interesting property is that all parts of the result that depend
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on the sign of the multiplication are discarded. Those would be the
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multiplications involving R1.h and R3.h, but only the top 16 bit of
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the 32 bit result depend on the sign, and since R1.h and R3.h only
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occur in E1, the top half of these results is cut off.
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So, we can just use FU mode for all of the 16-bit multiplies, and
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ignore questions of when to use mixed mode. */
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___muldi3:
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/* [SP] technically is part of the caller's frame, but we can
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use it as scratch space. */
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A0 = R2.H * R1.L, A1 = R2.L * R1.H (FU) || R3 = [SP + 12]; /* E1 */
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A0 += R3.H * R0.L, A1 += R3.L * R0.H (FU) || [SP] = R4; /* E1 */
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A0 += A1; /* E1 */
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R4 = A0.w;
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A0 = R0.l * R3.l (FU); /* E2 */
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A0 += R2.l * R1.l (FU); /* E2 */
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A1 = R2.L * R0.L (FU); /* E4 */
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R3 = A1.w;
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A1 = A1 >> 16; /* E3c */
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A0 += R2.H * R0.H, A1 += R2.L * R0.H (FU); /* E2, E3c */
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A1 += R0.L * R2.H (FU); /* E3c */
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R0 = A1.w;
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A1 = A1 >> 16; /* E2c */
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A0 += A1; /* E2c */
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R1 = A0.w;
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/* low(result) = low(E3c):low(E4) */
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R0 = PACK (R0.l, R3.l);
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/* high(result) = E2c + (E1 << 16) */
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R1.h = R1.h + R4.l (NS) || R4 = [SP];
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RTS;
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.size ___muldi3, .-___muldi3
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#endif
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