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Diffstat (limited to 'src/runtime/time_windows_arm.s')
| -rw-r--r-- | src/runtime/time_windows_arm.s | 90 |
1 files changed, 90 insertions, 0 deletions
diff --git a/src/runtime/time_windows_arm.s b/src/runtime/time_windows_arm.s new file mode 100644 index 0000000..711af88 --- /dev/null +++ b/src/runtime/time_windows_arm.s @@ -0,0 +1,90 @@ +// 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|NOFRAME,$0-20 + MOVW $0, R0 + MOVB runtime·useQPCTime(SB), R0 + CMP $0, R0 + BNE useQPC + 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 +useQPC: + B runtime·nowQPC(SB) // tail call + |