| // Copyright 2018 The Go Authors. All rights reserved. |
| // Use of this source code is governed by a BSD-style |
| // license that can be found in the LICENSE file. |
| |
| //go:build !faketime |
| |
| #include "go_asm.h" |
| #include "textflag.h" |
| #include "time_windows.h" |
| |
| TEXT time·now(SB),NOSPLIT,$0-20 |
| MOVW $_INTERRUPT_TIME, R3 |
| loop: |
| MOVW time_hi1(R3), R1 |
| DMB MB_ISH |
| MOVW time_lo(R3), R0 |
| DMB MB_ISH |
| MOVW time_hi2(R3), R2 |
| CMP R1, R2 |
| BNE loop |
| |
| // wintime = R1:R0, multiply by 100 |
| MOVW $100, R2 |
| MULLU R0, R2, (R4, R3) // R4:R3 = R1:R0 * R2 |
| MULA R1, R2, R4, R4 |
| |
| // wintime*100 = R4:R3 |
| MOVW R3, mono+12(FP) |
| MOVW R4, mono+16(FP) |
| |
| MOVW $_SYSTEM_TIME, R3 |
| wall: |
| MOVW time_hi1(R3), R1 |
| DMB MB_ISH |
| MOVW time_lo(R3), R0 |
| DMB MB_ISH |
| MOVW time_hi2(R3), R2 |
| CMP R1, R2 |
| BNE wall |
| |
| // w = R1:R0 in 100ns untis |
| // convert to Unix epoch (but still 100ns units) |
| #define delta 116444736000000000 |
| SUB.S $(delta & 0xFFFFFFFF), R0 |
| SBC $(delta >> 32), R1 |
| |
| // Convert to nSec |
| MOVW $100, R2 |
| MULLU R0, R2, (R4, R3) // R4:R3 = R1:R0 * R2 |
| MULA R1, R2, R4, R4 |
| // w = R2:R1 in nSec |
| MOVW R3, R1 // R4:R3 -> R2:R1 |
| MOVW R4, R2 |
| |
| // multiply nanoseconds by reciprocal of 10**9 (scaled by 2**61) |
| // to get seconds (96 bit scaled result) |
| MOVW $0x89705f41, R3 // 2**61 * 10**-9 |
| MULLU R1,R3,(R6,R5) // R7:R6:R5 = R2:R1 * R3 |
| MOVW $0,R7 |
| MULALU R2,R3,(R7,R6) |
| |
| // unscale by discarding low 32 bits, shifting the rest by 29 |
| MOVW R6>>29,R6 // R7:R6 = (R7:R6:R5 >> 61) |
| ORR R7<<3,R6 |
| MOVW R7>>29,R7 |
| |
| // subtract (10**9 * sec) from nsec to get nanosecond remainder |
| MOVW $1000000000, R5 // 10**9 |
| MULLU R6,R5,(R9,R8) // R9:R8 = R7:R6 * R5 |
| MULA R7,R5,R9,R9 |
| SUB.S R8,R1 // R2:R1 -= R9:R8 |
| SBC R9,R2 |
| |
| // because reciprocal was a truncated repeating fraction, quotient |
| // may be slightly too small -- adjust to make remainder < 10**9 |
| CMP R5,R1 // if remainder > 10**9 |
| SUB.HS R5,R1 // remainder -= 10**9 |
| ADD.HS $1,R6 // sec += 1 |
| |
| MOVW R6,sec_lo+0(FP) |
| MOVW R7,sec_hi+4(FP) |
| MOVW R1,nsec+8(FP) |
| RET |
| |
