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Diffstat (limited to 'runtime/arm/i64_shl.S')
| -rw-r--r-- | runtime/arm/i64_shl.S | 71 |
1 files changed, 71 insertions, 0 deletions
diff --git a/runtime/arm/i64_shl.S b/runtime/arm/i64_shl.S new file mode 100644 index 0000000..66569d3 --- /dev/null +++ b/runtime/arm/i64_shl.S @@ -0,0 +1,71 @@ +@ ***************************************************************** +@ +@ The Compcert verified compiler +@ +@ Xavier Leroy, INRIA Paris-Rocquencourt +@ +@ Copyright (c) 2013 Institut National de Recherche en Informatique et +@ en Automatique. +@ +@ Redistribution and use in source and binary forms, with or without +@ modification, are permitted provided that the following conditions are met: +@ * Redistributions of source code must retain the above copyright +@ notice, this list of conditions and the following disclaimer. +@ * Redistributions in binary form must reproduce the above copyright +@ notice, this list of conditions and the following disclaimer in the +@ documentation and/or other materials provided with the distribution. +@ * Neither the name of the <organization> nor the +@ names of its contributors may be used to endorse or promote products +@ derived from this software without specific prior written permission. +@ +@ THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS +@ "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT +@ LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR +@ A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL <COPYRIGHT +@ HOLDER> BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, +@ EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, +@ PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR +@ PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF +@ LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING +@ NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS +@ SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. +@ +@ ********************************************************************* + +@ Helper functions for 64-bit integer arithmetic. ARM version. + +#include "sysdeps.h" + +@@@ Shift left + +@ Note on ARM shifts: the shift amount is taken modulo 256. +@ If shift amount mod 256 >= 32, the shift produces 0. + +@ Algorithm: +@ RH = (XH << N) | (XL >> (32-N) | (XL << (N-32)) +@ RL = XL << N +@ If N = 0: +@ RH = XH | 0 | 0 +@ RL = XL +@ If 1 <= N <= 31: 1 <= 32-N <= 31 and 2s5 <= N-32 mod 256 <= 255 +@ RH = (XH << N) | (XL >> (32-N) | 0 +@ RL = XL << N +@ If N = 32: +@ RH = 0 | XL | 0 +@ RL = 0 +@ If 33 <= N <= 63: 225 <= 32-N mod 256 <= 255 and 1 <= N-32 <= 31 +@ RH = 0 | 0 | (XL << (N-32)) +@ RL = 0 + +FUNCTION(__i64_shl) + AND r2, r2, #63 @ normalize amount to 0...63 + RSB r3, r2, #32 @ r3 = 32 - amount + LSL r1, r1, r2 + LSR r3, r0, r3 + ORR r1, r1, r3 + SUB r3, r2, #32 @ r3 = amount - 32 + LSL r3, r0, r3 + ORR r1, r1, r3 + LSL r0, r0, r2 + bx lr +ENDFUNCTION(__i64_shl) |