Brad Fitzpatrick | 5194744 | 2016-03-01 22:57:46 +0000 | [diff] [blame] | 1 | // Copyright 2012 The Go Authors. All rights reserved. |
Russ Cox | dd8dc6f | 2011-12-13 15:20:12 -0500 | [diff] [blame] | 2 | // Use of this source code is governed by a BSD-style |
| 3 | // license that can be found in the LICENSE file. |
| 4 | |
Rob Pike | 8bca148 | 2014-08-12 17:04:45 -0700 | [diff] [blame] | 5 | #include "textflag.h" |
Keith Randall | 1f79663 | 2013-08-12 10:25:18 -0700 | [diff] [blame] | 6 | |
Charles L. Dorian | 322057c | 2012-06-02 13:06:12 -0400 | [diff] [blame] | 7 | #define Big 0x4330000000000000 // 2**52 |
| 8 | |
| 9 | // func Floor(x float64) float64 |
Keith Randall | 1f79663 | 2013-08-12 10:25:18 -0700 | [diff] [blame] | 10 | TEXT ·Floor(SB),NOSPLIT,$0 |
Charles L. Dorian | 322057c | 2012-06-02 13:06:12 -0400 | [diff] [blame] | 11 | MOVQ x+0(FP), AX |
| 12 | MOVQ $~(1<<63), DX // sign bit mask |
| 13 | ANDQ AX,DX // DX = |x| |
| 14 | SUBQ $1,DX |
| 15 | MOVQ $(Big - 1), CX // if |x| >= 2**52-1 or IsNaN(x) or |x| == 0, return x |
| 16 | CMPQ DX,CX |
| 17 | JAE isBig_floor |
| 18 | MOVQ AX, X0 // X0 = x |
| 19 | CVTTSD2SQ X0, AX |
| 20 | CVTSQ2SD AX, X1 // X1 = float(int(x)) |
| 21 | CMPSD X1, X0, 1 // compare LT; X0 = 0xffffffffffffffff or 0 |
| 22 | MOVSD $(-1.0), X2 |
| 23 | ANDPD X2, X0 // if x < float(int(x)) {X0 = -1} else {X0 = 0} |
| 24 | ADDSD X1, X0 |
Russ Cox | 07720b6 | 2013-03-22 12:57:55 -0400 | [diff] [blame] | 25 | MOVSD X0, ret+8(FP) |
Charles L. Dorian | 322057c | 2012-06-02 13:06:12 -0400 | [diff] [blame] | 26 | RET |
| 27 | isBig_floor: |
Russ Cox | 07720b6 | 2013-03-22 12:57:55 -0400 | [diff] [blame] | 28 | MOVQ AX, ret+8(FP) // return x |
Charles L. Dorian | 322057c | 2012-06-02 13:06:12 -0400 | [diff] [blame] | 29 | RET |
Russ Cox | dd8dc6f | 2011-12-13 15:20:12 -0500 | [diff] [blame] | 30 | |
Charles L. Dorian | 322057c | 2012-06-02 13:06:12 -0400 | [diff] [blame] | 31 | // func Ceil(x float64) float64 |
Keith Randall | 1f79663 | 2013-08-12 10:25:18 -0700 | [diff] [blame] | 32 | TEXT ·Ceil(SB),NOSPLIT,$0 |
Charles L. Dorian | 322057c | 2012-06-02 13:06:12 -0400 | [diff] [blame] | 33 | MOVQ x+0(FP), AX |
| 34 | MOVQ $~(1<<63), DX // sign bit mask |
| 35 | MOVQ AX, BX // BX = copy of x |
| 36 | ANDQ DX, BX // BX = |x| |
| 37 | MOVQ $Big, CX // if |x| >= 2**52 or IsNaN(x), return x |
| 38 | CMPQ BX, CX |
| 39 | JAE isBig_ceil |
| 40 | MOVQ AX, X0 // X0 = x |
| 41 | MOVQ DX, X2 // X2 = sign bit mask |
| 42 | CVTTSD2SQ X0, AX |
| 43 | ANDNPD X0, X2 // X2 = sign |
| 44 | CVTSQ2SD AX, X1 // X1 = float(int(x)) |
| 45 | CMPSD X1, X0, 2 // compare LE; X0 = 0xffffffffffffffff or 0 |
| 46 | ORPD X2, X1 // if X1 = 0.0, incorporate sign |
| 47 | MOVSD $1.0, X3 |
| 48 | ANDNPD X3, X0 |
| 49 | ORPD X2, X0 // if float(int(x)) <= x {X0 = 1} else {X0 = -0} |
| 50 | ADDSD X1, X0 |
Russ Cox | 07720b6 | 2013-03-22 12:57:55 -0400 | [diff] [blame] | 51 | MOVSD X0, ret+8(FP) |
Charles L. Dorian | 322057c | 2012-06-02 13:06:12 -0400 | [diff] [blame] | 52 | RET |
| 53 | isBig_ceil: |
Russ Cox | 07720b6 | 2013-03-22 12:57:55 -0400 | [diff] [blame] | 54 | MOVQ AX, ret+8(FP) |
Charles L. Dorian | 322057c | 2012-06-02 13:06:12 -0400 | [diff] [blame] | 55 | RET |
Russ Cox | dd8dc6f | 2011-12-13 15:20:12 -0500 | [diff] [blame] | 56 | |
Charles L. Dorian | 322057c | 2012-06-02 13:06:12 -0400 | [diff] [blame] | 57 | // func Trunc(x float64) float64 |
Keith Randall | 1f79663 | 2013-08-12 10:25:18 -0700 | [diff] [blame] | 58 | TEXT ·Trunc(SB),NOSPLIT,$0 |
Charles L. Dorian | 322057c | 2012-06-02 13:06:12 -0400 | [diff] [blame] | 59 | MOVQ x+0(FP), AX |
| 60 | MOVQ $~(1<<63), DX // sign bit mask |
| 61 | MOVQ AX, BX // BX = copy of x |
| 62 | ANDQ DX, BX // BX = |x| |
| 63 | MOVQ $Big, CX // if |x| >= 2**52 or IsNaN(x), return x |
| 64 | CMPQ BX, CX |
| 65 | JAE isBig_trunc |
| 66 | MOVQ AX, X0 |
| 67 | MOVQ DX, X2 // X2 = sign bit mask |
| 68 | CVTTSD2SQ X0, AX |
| 69 | ANDNPD X0, X2 // X2 = sign |
| 70 | CVTSQ2SD AX, X0 // X0 = float(int(x)) |
| 71 | ORPD X2, X0 // if X0 = 0.0, incorporate sign |
Russ Cox | 07720b6 | 2013-03-22 12:57:55 -0400 | [diff] [blame] | 72 | MOVSD X0, ret+8(FP) |
Charles L. Dorian | 322057c | 2012-06-02 13:06:12 -0400 | [diff] [blame] | 73 | RET |
| 74 | isBig_trunc: |
Russ Cox | 07720b6 | 2013-03-22 12:57:55 -0400 | [diff] [blame] | 75 | MOVQ AX, ret+8(FP) // return x |
Charles L. Dorian | 322057c | 2012-06-02 13:06:12 -0400 | [diff] [blame] | 76 | RET |