From 41e501aaf4fc218a121aeaff9e8a01c9a18da874 Mon Sep 17 00:00:00 2001
From: Ayke van Laethem <aykevanlaethem@gmail.com>
Date: Sat, 12 Apr 2025 12:54:06 +0200
Subject: [PATCH] runtime: move timeUnit to a single place

The timeUnit is now the same type everywhere. Move it to a single place
and add some documentation to it.
---
 src/runtime/runtime.go                  | 11 +++++++++++
 src/runtime/runtime_arm7tdmi.go         |  2 --
 src/runtime/runtime_atsamd21.go         |  2 --
 src/runtime/runtime_atsamd51.go         |  2 --
 src/runtime/runtime_avr.go              |  3 ---
 src/runtime/runtime_avrtiny.go          |  2 --
 src/runtime/runtime_cortexm_qemu.go     |  2 --
 src/runtime/runtime_esp32xx.go          |  2 --
 src/runtime/runtime_esp8266.go          |  2 --
 src/runtime/runtime_fe310.go            |  2 --
 src/runtime/runtime_k210.go             |  2 --
 src/runtime/runtime_mimxrt1062_time.go  |  2 --
 src/runtime/runtime_nintendoswitch.go   |  2 --
 src/runtime/runtime_nrf.go              |  2 --
 src/runtime/runtime_nrf52840.go         |  2 --
 src/runtime/runtime_rp2040.go           |  2 --
 src/runtime/runtime_rp2350.go           |  2 --
 src/runtime/runtime_stm32.go            |  2 --
 src/runtime/runtime_tinygoriscv_qemu.go |  6 ++----
 src/runtime/runtime_tkey.go             |  2 --
 src/runtime/runtime_unix.go             |  2 --
 src/runtime/runtime_wasip1.go           |  2 --
 src/runtime/runtime_wasip2.go           |  2 --
 src/runtime/runtime_wasm_js.go          |  2 --
 src/runtime/runtime_wasm_unknown.go     |  5 -----
 src/runtime/runtime_windows.go          |  2 --
 src/runtime/time_nxpmk66f18.go          |  2 --
 27 files changed, 13 insertions(+), 58 deletions(-)

diff --git a/src/runtime/runtime.go b/src/runtime/runtime.go
index 99ca34f2c..2dcf313ff 100644
--- a/src/runtime/runtime.go
+++ b/src/runtime/runtime.go
@@ -8,6 +8,17 @@ import (
 
 const Compiler = "tinygo"
 
+// Unit for the 'ticks' and 'sleepTicks' functions.
+//
+// This is the native time unit for the given system. One timeUnit tick might be
+// 1ns or 100ns on a desktop system, or 1/32768s on baremetal systems with a
+// low-power RTC. Many other tick durations are possible.
+//
+// Conversion from time units to nanoseconds and back is done using
+// ticksToNanoseconds and nanosecondsToTicks, which need to be implemented for
+// each system as needed.
+type timeUnit int64
+
 // The compiler will fill this with calls to the initialization function of each
 // package.
 func initAll()
diff --git a/src/runtime/runtime_arm7tdmi.go b/src/runtime/runtime_arm7tdmi.go
index d63b229c2..fe0b648b5 100644
--- a/src/runtime/runtime_arm7tdmi.go
+++ b/src/runtime/runtime_arm7tdmi.go
@@ -7,8 +7,6 @@ import (
 	"unsafe"
 )
 
-type timeUnit int64
-
 func putchar(c byte) {
 	// dummy, TODO
 }
diff --git a/src/runtime/runtime_atsamd21.go b/src/runtime/runtime_atsamd21.go
index d30fc7f6f..e0aeb0869 100644
--- a/src/runtime/runtime_atsamd21.go
+++ b/src/runtime/runtime_atsamd21.go
@@ -12,8 +12,6 @@ import (
 	"unsafe"
 )
 
-type timeUnit int64
-
 //export Reset_Handler
 func main() {
 	preinit()
diff --git a/src/runtime/runtime_atsamd51.go b/src/runtime/runtime_atsamd51.go
index 151f81581..5c8a3d8b2 100644
--- a/src/runtime/runtime_atsamd51.go
+++ b/src/runtime/runtime_atsamd51.go
@@ -11,8 +11,6 @@ import (
 	"runtime/volatile"
 )
 
-type timeUnit int64
-
 //export Reset_Handler
 func main() {
 	arm.SCB.CPACR.Set(0) // disable FPU if it is enabled
diff --git a/src/runtime/runtime_avr.go b/src/runtime/runtime_avr.go
index 43d35d7b9..7274748af 100644
--- a/src/runtime/runtime_avr.go
+++ b/src/runtime/runtime_avr.go
@@ -12,9 +12,6 @@ import (
 
 const BOARD = "arduino"
 
-// timeUnit in nanoseconds
-type timeUnit int64
-
 // Watchdog timer periods. These can be off by a large margin (hence the jump
 // between 64ms and 125ms which is not an exact double), so don't rely on this
 // for accurate time keeping.
diff --git a/src/runtime/runtime_avrtiny.go b/src/runtime/runtime_avrtiny.go
index 8ce324938..e8ffd17cd 100644
--- a/src/runtime/runtime_avrtiny.go
+++ b/src/runtime/runtime_avrtiny.go
@@ -22,8 +22,6 @@ import (
 	"runtime/volatile"
 )
 
-type timeUnit int64
-
 //export main
 func main() {
 	// Initialize RTC.
diff --git a/src/runtime/runtime_cortexm_qemu.go b/src/runtime/runtime_cortexm_qemu.go
index 22bfee167..f15e92be8 100644
--- a/src/runtime/runtime_cortexm_qemu.go
+++ b/src/runtime/runtime_cortexm_qemu.go
@@ -11,8 +11,6 @@ import (
 	"unsafe"
 )
 
-type timeUnit int64
-
 var timestamp timeUnit
 
 //export Reset_Handler
diff --git a/src/runtime/runtime_esp32xx.go b/src/runtime/runtime_esp32xx.go
index e4fe8835a..f1c62243f 100644
--- a/src/runtime/runtime_esp32xx.go
+++ b/src/runtime/runtime_esp32xx.go
@@ -8,8 +8,6 @@ import (
 	"unsafe"
 )
 
-type timeUnit int64
-
 // Initialize .bss: zero-initialized global variables.
 // The .data section has already been loaded by the ROM bootloader.
 func clearbss() {
diff --git a/src/runtime/runtime_esp8266.go b/src/runtime/runtime_esp8266.go
index b12a8b68f..6dd0f83e0 100644
--- a/src/runtime/runtime_esp8266.go
+++ b/src/runtime/runtime_esp8266.go
@@ -9,8 +9,6 @@ import (
 	"unsafe"
 )
 
-type timeUnit int64
-
 var currentTime timeUnit = 0
 
 func putchar(c byte) {
diff --git a/src/runtime/runtime_fe310.go b/src/runtime/runtime_fe310.go
index 218962edb..99d253af0 100644
--- a/src/runtime/runtime_fe310.go
+++ b/src/runtime/runtime_fe310.go
@@ -14,8 +14,6 @@ import (
 	"runtime/volatile"
 )
 
-type timeUnit int64
-
 //export main
 func main() {
 	// Zero the PLIC enable bits on startup: they are not zeroed at reset.
diff --git a/src/runtime/runtime_k210.go b/src/runtime/runtime_k210.go
index 8ee79b938..61b6bfa3e 100644
--- a/src/runtime/runtime_k210.go
+++ b/src/runtime/runtime_k210.go
@@ -13,8 +13,6 @@ import (
 	"unsafe"
 )
 
-type timeUnit int64
-
 //export main
 func main() {
 
diff --git a/src/runtime/runtime_mimxrt1062_time.go b/src/runtime/runtime_mimxrt1062_time.go
index feaf68dbd..382ba1c6f 100644
--- a/src/runtime/runtime_mimxrt1062_time.go
+++ b/src/runtime/runtime_mimxrt1062_time.go
@@ -10,8 +10,6 @@ import (
 	"unsafe"
 )
 
-type timeUnit int64
-
 const (
 	lastCycle      = SYSTICK_FREQ/1000 - 1
 	cyclesPerMicro = CORE_FREQ / 1000000
diff --git a/src/runtime/runtime_nintendoswitch.go b/src/runtime/runtime_nintendoswitch.go
index 2d3677bf0..074e18287 100644
--- a/src/runtime/runtime_nintendoswitch.go
+++ b/src/runtime/runtime_nintendoswitch.go
@@ -4,8 +4,6 @@ package runtime
 
 import "unsafe"
 
-type timeUnit int64
-
 const (
 	// Handles
 	infoTypeTotalMemorySize = 6          // Total amount of memory available for process.
diff --git a/src/runtime/runtime_nrf.go b/src/runtime/runtime_nrf.go
index 729c6bb20..a295b9966 100644
--- a/src/runtime/runtime_nrf.go
+++ b/src/runtime/runtime_nrf.go
@@ -10,8 +10,6 @@ import (
 	"runtime/volatile"
 )
 
-type timeUnit int64
-
 //go:linkname systemInit SystemInit
 func systemInit()
 
diff --git a/src/runtime/runtime_nrf52840.go b/src/runtime/runtime_nrf52840.go
index 41c36fe5f..4ac7314a2 100644
--- a/src/runtime/runtime_nrf52840.go
+++ b/src/runtime/runtime_nrf52840.go
@@ -11,8 +11,6 @@ import (
 	"runtime/volatile"
 )
 
-type timeUnit int64
-
 //go:linkname systemInit SystemInit
 func systemInit()
 
diff --git a/src/runtime/runtime_rp2040.go b/src/runtime/runtime_rp2040.go
index 1d36a771e..fb1d1ddbd 100644
--- a/src/runtime/runtime_rp2040.go
+++ b/src/runtime/runtime_rp2040.go
@@ -14,8 +14,6 @@ func machineTicks() uint64
 // machineLightSleep is provided by package machine.
 func machineLightSleep(uint64)
 
-type timeUnit int64
-
 // ticks returns the number of ticks (microseconds) elapsed since power up.
 func ticks() timeUnit {
 	t := machineTicks()
diff --git a/src/runtime/runtime_rp2350.go b/src/runtime/runtime_rp2350.go
index f70ec413c..500e4c9f2 100644
--- a/src/runtime/runtime_rp2350.go
+++ b/src/runtime/runtime_rp2350.go
@@ -14,8 +14,6 @@ func machineTicks() uint64
 // machineLightSleep is provided by package machine.
 func machineLightSleep(uint64)
 
-type timeUnit int64
-
 // ticks returns the number of ticks (microseconds) elapsed since power up.
 func ticks() timeUnit {
 	t := machineTicks()
diff --git a/src/runtime/runtime_stm32.go b/src/runtime/runtime_stm32.go
index c212ead72..c4f2ef660 100644
--- a/src/runtime/runtime_stm32.go
+++ b/src/runtime/runtime_stm32.go
@@ -4,8 +4,6 @@ package runtime
 
 import "device/arm"
 
-type timeUnit int64
-
 //export Reset_Handler
 func main() {
 	preinit()
diff --git a/src/runtime/runtime_tinygoriscv_qemu.go b/src/runtime/runtime_tinygoriscv_qemu.go
index e58e75351..a77ad71f5 100644
--- a/src/runtime/runtime_tinygoriscv_qemu.go
+++ b/src/runtime/runtime_tinygoriscv_qemu.go
@@ -11,10 +11,6 @@ import (
 // This file implements the VirtIO RISC-V interface implemented in QEMU, which
 // is an interface designed for emulation.
 
-// One tick is 100ns by default in QEMU.
-// (This is not a standard, just the default used by QEMU).
-type timeUnit int64
-
 //export main
 func main() {
 	preinit()
@@ -61,6 +57,8 @@ func handleInterrupt() {
 	riscv.MCAUSE.Set(0)
 }
 
+// One tick is 100ns by default in QEMU.
+// (This is not a standard, just the default used by QEMU).
 func ticksToNanoseconds(ticks timeUnit) int64 {
 	return int64(ticks) * 100 // one tick is 100ns
 }
diff --git a/src/runtime/runtime_tkey.go b/src/runtime/runtime_tkey.go
index ba8c5e944..87628c62e 100644
--- a/src/runtime/runtime_tkey.go
+++ b/src/runtime/runtime_tkey.go
@@ -10,8 +10,6 @@ import (
 	"runtime/volatile"
 )
 
-type timeUnit int64
-
 //export main
 func main() {
 	preinit()
diff --git a/src/runtime/runtime_unix.go b/src/runtime/runtime_unix.go
index 3724c457c..99f28411f 100644
--- a/src/runtime/runtime_unix.go
+++ b/src/runtime/runtime_unix.go
@@ -61,8 +61,6 @@ func clock_gettime(clk_id int32, ts *timespec) {
 	}
 }
 
-type timeUnit int64
-
 // Note: tv_sec and tv_nsec normally vary in size by platform. However, we're
 // using the time64 variant (see clock_gettime above), so the formats are the
 // same between 32-bit and 64-bit architectures.
diff --git a/src/runtime/runtime_wasip1.go b/src/runtime/runtime_wasip1.go
index 92adb9bef..d680fad17 100644
--- a/src/runtime/runtime_wasip1.go
+++ b/src/runtime/runtime_wasip1.go
@@ -6,8 +6,6 @@ import (
 	"unsafe"
 )
 
-type timeUnit int64
-
 // libc constructors
 //
 //export __wasm_call_ctors
diff --git a/src/runtime/runtime_wasip2.go b/src/runtime/runtime_wasip2.go
index 296f4a45b..46ce3d853 100644
--- a/src/runtime/runtime_wasip2.go
+++ b/src/runtime/runtime_wasip2.go
@@ -12,8 +12,6 @@ import (
 	"internal/cm"
 )
 
-type timeUnit int64
-
 func init() {
 	wasiclirun.Exports.Run = func() cm.BoolResult {
 		callMain()
diff --git a/src/runtime/runtime_wasm_js.go b/src/runtime/runtime_wasm_js.go
index 1766cd7e6..92359e4da 100644
--- a/src/runtime/runtime_wasm_js.go
+++ b/src/runtime/runtime_wasm_js.go
@@ -2,8 +2,6 @@
 
 package runtime
 
-type timeUnit int64
-
 var handleEvent func()
 
 //go:linkname setEventHandler syscall/js.setEventHandler
diff --git a/src/runtime/runtime_wasm_unknown.go b/src/runtime/runtime_wasm_unknown.go
index 27e248579..70c42f2a9 100644
--- a/src/runtime/runtime_wasm_unknown.go
+++ b/src/runtime/runtime_wasm_unknown.go
@@ -5,8 +5,6 @@ package runtime
 // TODO: this is essentially reactor mode wasm. So we might want to support
 // -buildmode=c-shared (and default to it).
 
-type timeUnit int64
-
 // libc constructors
 //
 //export __wasm_call_ctors
@@ -24,9 +22,6 @@ func nanosecondsToTicks(ns int64) timeUnit {
 	return timeUnit(ns)
 }
 
-// with the wasm32-unknown-unknown target there is no way to determine any `precision`
-const timePrecisionNanoseconds = 1000
-
 func sleepTicks(d timeUnit) {
 }
 
diff --git a/src/runtime/runtime_windows.go b/src/runtime/runtime_windows.go
index 88857fc3a..17ee2ce72 100644
--- a/src/runtime/runtime_windows.go
+++ b/src/runtime/runtime_windows.go
@@ -123,8 +123,6 @@ func preinit() {
 	heapEnd = heapStart + heapSize
 }
 
-type timeUnit int64
-
 var stackTop uintptr
 
 func ticksToNanoseconds(ticks timeUnit) int64 {
diff --git a/src/runtime/time_nxpmk66f18.go b/src/runtime/time_nxpmk66f18.go
index ca3120f84..d6114556a 100644
--- a/src/runtime/time_nxpmk66f18.go
+++ b/src/runtime/time_nxpmk66f18.go
@@ -39,8 +39,6 @@ import (
 	"runtime/volatile"
 )
 
-type timeUnit int64
-
 func ticksToNanoseconds(ticks timeUnit) int64 {
 	return int64(ticks) * 1000
 }