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Diffstat (limited to 'sysdeps/alpha/divqu.S')
| -rw-r--r-- | sysdeps/alpha/divqu.S | 257 |
1 files changed, 0 insertions, 257 deletions
diff --git a/sysdeps/alpha/divqu.S b/sysdeps/alpha/divqu.S deleted file mode 100644 index ef3cdb1b2b..0000000000 --- a/sysdeps/alpha/divqu.S +++ /dev/null @@ -1,257 +0,0 @@ -/* Copyright (C) 2004 Free Software Foundation, Inc. - This file is part of the GNU C Library. - - The GNU C Library is free software; you can redistribute it and/or - modify it under the terms of the GNU Lesser General Public - License as published by the Free Software Foundation; either - version 2.1 of the License, or (at your option) any later version. - - The GNU C Library is distributed in the hope that it will be useful, - but WITHOUT ANY WARRANTY; without even the implied warranty of - MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU - Lesser General Public License for more details. - - You should have received a copy of the GNU Lesser General Public - License along with the GNU C Library; if not, write to the Free - Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA - 02111-1307 USA. */ - -#include "div_libc.h" - - -/* 64-bit unsigned long divide. These are not normal C functions. Argument - registers are t10 and t11, the result goes in t12. Only t12 and AT may be - clobbered. - - Theory of operation here is that we can use the FPU divider for virtually - all operands that we see: all dividend values between -2**53 and 2**53-1 - can be computed directly. Note that divisor values need not be checked - against that range because the rounded fp value will be close enough such - that the quotient is < 1, which will properly be truncated to zero when we - convert back to integer. - - When the dividend is outside the range for which we can compute exact - results, we use the fp quotent as an estimate from which we begin refining - an exact integral value. This reduces the number of iterations in the - shift-and-subtract loop significantly. - - The FPCR save/restore is due to the fact that the EV6 _will_ set FPCR_INE - for cvttq/c even without /sui being set. It will not, however, properly - raise the exception, so we don't have to worry about FPCR_INED being clear - and so dying by SIGFPE. */ - - .text - .align 4 - .globl __divqu - .type __divqu, @funcnoplt - .usepv __divqu, no - - cfi_startproc - cfi_return_column (RA) -__divqu: - lda sp, -FRAME(sp) - cfi_def_cfa_offset (FRAME) - CALL_MCOUNT - - /* Get the fp divide insn issued as quickly as possible. After - that's done, we have at least 22 cycles until its results are - ready -- all the time in the world to figure out how we're - going to use the results. */ - stt $f0, 0(sp) - excb - beq Y, DIVBYZERO - - stt $f1, 8(sp) - stt $f3, 48(sp) - cfi_rel_offset ($f0, 0) - cfi_rel_offset ($f1, 8) - cfi_rel_offset ($f3, 48) - mf_fpcr $f3 - - _ITOFT2 X, $f0, 16, Y, $f1, 24 - cvtqt $f0, $f0 - cvtqt $f1, $f1 - blt X, $x_is_neg - divt/c $f0, $f1, $f0 - - /* Check to see if Y was mis-converted as signed value. */ - ldt $f1, 8(sp) - blt Y, $y_is_neg - - /* Check to see if X fit in the double as an exact value. */ - srl X, 53, AT - bne AT, $x_big - - /* If we get here, we're expecting exact results from the division. - Do nothing else besides convert and clean up. */ - cvttq/c $f0, $f0 - excb - mt_fpcr $f3 - _FTOIT $f0, RV, 16 - - ldt $f0, 0(sp) - ldt $f3, 48(sp) - cfi_remember_state - cfi_restore ($f0) - cfi_restore ($f1) - cfi_restore ($f3) - cfi_def_cfa_offset (0) - lda sp, FRAME(sp) - ret $31, (RA), 1 - - .align 4 - cfi_restore_state -$x_is_neg: - /* If we get here, X is so big that bit 63 is set, which made the - conversion come out negative. Fix it up lest we not even get - a good estimate. */ - ldah AT, 0x5f80 /* 2**64 as float. */ - stt $f2, 24(sp) - cfi_rel_offset ($f2, 24) - _ITOFS AT, $f2, 16 - - .align 4 - addt $f0, $f2, $f0 - unop - divt/c $f0, $f1, $f0 - unop - - /* Ok, we've now the divide issued. Continue with other checks. */ - ldt $f1, 8(sp) - unop - ldt $f2, 24(sp) - blt Y, $y_is_neg - cfi_restore ($f1) - cfi_restore ($f2) - cfi_remember_state /* for y_is_neg */ - - .align 4 -$x_big: - /* If we get here, X is large enough that we don't expect exact - results, and neither X nor Y got mis-translated for the fp - division. Our task is to take the fp result, figure out how - far it's off from the correct result and compute a fixup. */ - stq t0, 16(sp) - stq t1, 24(sp) - stq t2, 32(sp) - stq t3, 40(sp) - cfi_rel_offset (t0, 16) - cfi_rel_offset (t1, 24) - cfi_rel_offset (t2, 32) - cfi_rel_offset (t3, 40) - -#define Q RV /* quotient */ -#define R t0 /* remainder */ -#define SY t1 /* scaled Y */ -#define S t2 /* scalar */ -#define QY t3 /* Q*Y */ - - cvttq/c $f0, $f0 - _FTOIT $f0, Q, 8 - mulq Q, Y, QY - - .align 4 - stq t4, 8(sp) - excb - ldt $f0, 0(sp) - mt_fpcr $f3 - cfi_rel_offset (t4, 8) - cfi_restore ($f0) - - subq QY, X, R - mov Y, SY - mov 1, S - bgt R, $q_high - -$q_high_ret: - subq X, QY, R - mov Y, SY - mov 1, S - bgt R, $q_low - -$q_low_ret: - ldq t4, 8(sp) - ldq t0, 16(sp) - ldq t1, 24(sp) - ldq t2, 32(sp) - - ldq t3, 40(sp) - ldt $f3, 48(sp) - lda sp, FRAME(sp) - cfi_remember_state - cfi_restore (t0) - cfi_restore (t1) - cfi_restore (t2) - cfi_restore (t3) - cfi_restore (t4) - cfi_restore ($f3) - cfi_def_cfa_offset (0) - ret $31, (RA), 1 - - .align 4 - cfi_restore_state - /* The quotient that we computed was too large. We need to reduce - it by S such that Y*S >= R. Obviously the closer we get to the - correct value the better, but overshooting high is ok, as we'll - fix that up later. */ -0: - addq SY, SY, SY - addq S, S, S -$q_high: - cmpult SY, R, AT - bne AT, 0b - - subq Q, S, Q - unop - subq QY, SY, QY - br $q_high_ret - - .align 4 - /* The quotient that we computed was too small. Divide Y by the - current remainder (R) and add that to the existing quotient (Q). - The expectation, of course, is that R is much smaller than X. */ - /* Begin with a shift-up loop. Compute S such that Y*S >= R. We - already have a copy of Y in SY and the value 1 in S. */ -0: - addq SY, SY, SY - addq S, S, S -$q_low: - cmpult SY, R, AT - bne AT, 0b - - /* Shift-down and subtract loop. Each iteration compares our scaled - Y (SY) with the remainder (R); if SY <= R then X is divisible by - Y's scalar (S) so add it to the quotient (Q). */ -2: addq Q, S, t3 - srl S, 1, S - cmpule SY, R, AT - subq R, SY, t4 - - cmovne AT, t3, Q - cmovne AT, t4, R - srl SY, 1, SY - bne S, 2b - - br $q_low_ret - - .align 4 - cfi_restore_state -$y_is_neg: - /* If we get here, Y is so big that bit 63 is set. The results - from the divide will be completely wrong. Fortunately, the - quotient must be either 0 or 1, so just compute it directly. */ - cmpule Y, X, RV - excb - mt_fpcr $f3 - ldt $f0, 0(sp) - ldt $f3, 48(sp) - lda sp, FRAME(sp) - cfi_restore ($f0) - cfi_restore ($f3) - cfi_def_cfa_offset (0) - ret $31, (RA), 1 - - cfi_endproc - .size __divqu, .-__divqu - - DO_DIVBYZERO |