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Diffstat (limited to 'runtime/arm/i64_dtou.S')
| -rw-r--r-- | runtime/arm/i64_dtou.S | 75 |
1 files changed, 75 insertions, 0 deletions
diff --git a/runtime/arm/i64_dtou.S b/runtime/arm/i64_dtou.S new file mode 100644 index 0000000..7f6152e --- /dev/null +++ b/runtime/arm/i64_dtou.S @@ -0,0 +1,75 @@ +@ ***************************************************************** +@ +@ 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. + + .text + +@@@ Conversion from double float to unsigned 64-bit integer + + .global __i64_dtou +__i64_dtou: + cmp r1, #0 @ is double < 0 ? + blt 1f @ then it converts to 0 + @ extract unbiased exponent ((HI & 0x7FF00000) >> 20) - (1023 + 52) in r2 + @ note: 1023 + 52 = 1075 = 1024 + 51 + @ note: (HI & 0x7FF00000) >> 20 = (HI << 1) >> 21 + mov r2, r1, lsl #1 + mov r2, r2, lsr #21 + sub r2, r2, #51 + sub r2, r2, #1024 + @ check range of exponent + cmn r2, #52 @ if EXP < -52, double is < 1.0 + blt 1f + cmp r2, #12 @ if EXP >= 64 - 52, double is >= 2^64 + bge 2f + @ extract true mantissa + bic r1, r1, #0xFF000000 + bic r1, r1, #0x00F00000 @ HI &= ~0xFFF00000 + orr r1, r1, #0x00100000 @ HI |= 0x00100000 + @ shift it appropriately + cmp r2, #0 + bge __i64_shl @ if EXP >= 0, shift left by EXP + rsb r2, r2, #0 + b __i64_shr @ otherwise, shift right by -EXP + @ special cases +1: mov r0, #0 @ result is 0 + mov r1, #0 + bx lr +2: mvn r0, #0 @ result is 0xFF....FF (MAX_UINT) + mvn r1, #0 + bx lr + .type __i64_dtou, %function + .size __i64_dtou, . - __i64_dtou + |