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Diffstat (limited to 'runtime/arm/i64_dtos.S')
| -rw-r--r-- | runtime/arm/i64_dtos.S | 91 |
1 files changed, 91 insertions, 0 deletions
diff --git a/runtime/arm/i64_dtos.S b/runtime/arm/i64_dtos.S new file mode 100644 index 0000000..d0ef037 --- /dev/null +++ b/runtime/arm/i64_dtos.S @@ -0,0 +1,91 @@ +@ ***************************************************************** +@ +@ 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 signed 64-bit integer + + .global __i64_dtos +__i64_dtos: + push {r4, lr} + mov r4, r1, asr #31 @ save sign in r4 + @ 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, #11 @ if EXP >= 63 - 52, |double| is >= 2^63 + 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 + blt 3f + bl __i64_shl @ if EXP >= 0, shift left by EXP + b 4f +3: rsb r2, r2, #0 + bl __i64_shr @ otherwise, shift right by -EXP + @ apply sign to result +4: eor r0, r0, r4 + eor r1, r1, r4 + subs r0, r0, r4 + sbc r1, r1, r4 + pop {r4, lr} + bx lr + @ special cases +1: mov r0, #0 @ result is 0 + mov r1, #0 + pop {r4, lr} + bx lr +2: cmp r4, #0 + blt 6f + mvn r0, #0 @ result is 0x7F....FF (MAX_SINT) + mov r1, r0, lsr #1 + pop {r4, lr} + bx lr +6: mov r0, #0 @ result is 0x80....00 (MIN_SINT) + mov r1, #0x80000000 + pop {r4, lr} + bx lr + .type __i64_dtos, %function + .size __i64_dtos, . - __i64_dtos |