Time adjustments

Author: Ian Seyler

src/drivers/bus/xhci.asm

@@ -1486,14 +1486,14 @@ xhci_check_command_event:
 	push rsi
 	push rdx
 	push rcx
-	call os_hpet_us
+	call [sys_time]
 	mov rdx, rax
-	add rdx, 50000		; Add 50,000 μs
+	add rdx, 50000000	; Add 50,000,000 ns
 	mov rsi, os_usb_ERS	; Event segment for Command Ring
 	shl rcx, 12		; Quick multiply by 4096
 	add rsi, rcx
 load_event:
-	call os_hpet_us
+	call [sys_time]
 	cmp rax, rdx
 	ja xhci_check_command_event_timeout
 	mov rax, [rsi]

src/drivers/timer.asm

@@ -2,12 +2,15 @@
 ; BareMetal -- a 64-bit OS written in Assembly for x86-64 systems
 ; Copyright (C) 2008-2025 Return Infinity -- see LICENSE.TXT
 ;
-; Timer Functions
+; Time Functions
 ; =============================================================================
 
 
-; Note:	There are 1,000,000 microseconds in a second
-;	There are 1,000 milliseconds in a second
+; Note:	1,000,000,000,000,000 femtoseconds / second
+;	1,000,000,000,000 picoseconds /second
+;	1,000,000,000 nanoseconds / second
+;	1,000,000 microseconds / second
+;	1,000 milliseconds / second
 
 
 os_timer_init:
@@ -31,13 +34,15 @@ os_timer_init_phys:
 	jz os_timer_init_error
 	; Initialize the HPET
 	call init_timer_hpet
-	mov qword [sys_timer], hpet_delay
+	mov qword [sys_time], hpet_ns
+	mov qword [sys_delay], hpet_delay
 	jmp os_timer_init_done
 
 os_timer_init_kvm:
 	; Initialize the KVM timer
 	call init_timer_kvm
-	mov qword [sys_timer], kvm_delay
+	mov qword [sys_time], kvm_ns
+	mov qword [sys_delay], kvm_delay
 	jmp os_timer_init_done
 
 os_timer_init_error:
@@ -74,10 +79,10 @@ os_hpet_init_error:
 
 
 ; -----------------------------------------------------------------------------
-; os_hpet_us -- Get current microseconds (us) since HPET started
+; hpet_ns -- Get current nanoseconds (ns) since HPET started
 ; IN:	Nothing
 ; OUT:	RAX = Time in microseconds since start
-os_hpet_us:
+hpet_ns:
 	push rdx
 	push rcx
 
@@ -91,8 +96,8 @@ os_hpet_us:
 	mov ecx, [os_HPET_Frequency]
 	mul rcx				; RDX:RAX *= RCX
 
-	; Divide by # of femtoseconds in a microsecond
-	mov rcx, 1000000000
+	; Divide by # of femtoseconds in a nanosecond
+	mov rcx, 1000000
 	div rcx				; RAX = RDX:RAX / RCX
 
 	pop rcx
@@ -202,7 +207,7 @@ init_timer_kvm_configure:
 ; IN:	Nothing
 ; OUT:	RAX = microseconds elapsed since start
 ;	All other registers preserved
-kvm_get_usec:
+kvm_ns:
 	push r10
 	push r9
 	push rdi
@@ -211,10 +216,10 @@ kvm_get_usec:
 	push rbx
 
 	mov rdi, kvm_timer
-kvm_get_usec_wait:
+kvm_ns_wait:
 	mov r10d, [rdi]			; Get 32-bit version
 	test r10d, 1			; Check if version is odd (update in progress)
-	jnz kvm_get_usec_wait		; If so, retry
+	jnz kvm_ns_wait			; If so, retry
 
 	lfence
 
@@ -237,13 +242,13 @@ kvm_get_usec_wait:
 
 	; Apply tsc_shift
 	cmp cl, 0
-	jl kvm_get_usec_shift_right	; Signed comparison
+	jl kvm_ns_shift_right	; Signed comparison
 	shl rax, cl
-	jmp kvm_get_usec_shift_done
-kvm_get_usec_shift_right:
+	jmp kvm_ns_shift_done
+kvm_ns_shift_right:
 	neg cl				; Ex: 0xFF = tsc shift of -1
 	shr rax, cl
-kvm_get_usec_shift_done:
+kvm_ns_shift_done:
 
 	pop rcx				; Restore tsc_to_system_mul
 
@@ -260,12 +265,7 @@ kvm_get_usec_shift_done:
 	lfence
 	mov ecx, [rdi]			; Load 32-bit version
 	cmp r10d, ecx			; Compare to first version read
-	jne kvm_get_usec_wait		; If not equal then an update occured, restart
-
-	; Convert nanoseconds to microseconds
-	xor edx, edx
-	mov ecx, 1000
-	div rcx
+	jne kvm_ns_wait			; If not equal then an update occurred, restart
 
 	pop rbx
 	pop rcx
@@ -284,19 +284,27 @@ kvm_get_usec_shift_done:
 ; Note:	There are 1,000,000 microseconds in a second
 ;	There are 1,000 milliseconds in a second
 kvm_delay:
+	push rdx
+	push rcx
 	push rbx
 	push rax
 
+	; Multiply time by 1000 to convert to nanoseconds
+	mov ecx, 1000
+	mul rcx				; RDX:RAX = RAX * RCX
+
 	mov rbx, rax			; Store delay in RBX
-	call kvm_get_usec
+	call kvm_ns
 	add rbx, rax			; Add elapsed time
 kvm_delay_wait:
-	call kvm_get_usec
+	call kvm_ns
 	cmp rax, rbx
 	jb kvm_delay_wait
 
 	pop rax
 	pop rbx
+	pop rcx
+	pop rdx
 	ret
 ; -----------------------------------------------------------------------------
 
@@ -310,7 +318,7 @@ kvm_delay_wait:
 timer_delay:
 	push rax
 
-	call [sys_timer]
+	call [sys_delay]
 
 	pop rax
 	ret

src/syscalls/system.asm

@@ -31,7 +31,7 @@ b_system_end:
 ; Basic
 
 b_system_timecounter:
-	;TODO
+	call [sys_time]
 	ret
 
 b_system_free_memory:
@@ -154,7 +154,7 @@ b_system_debug_dump_rax:
 	ret
 
 b_system_delay:
-	call b_delay
+	call [sys_delay]
 	ret
 
 b_system_reset:

src/sysvar.asm

@@ -74,7 +74,8 @@ os_IOAPICAddress:	equ os_SystemVariables + 0x0008
 os_SysConfEn:		equ os_SystemVariables + 0x0010	; Enabled bits: 0=PS/2 Keyboard, 2=Serial, 4=HPET, 5=xHCI
 os_StackBase:		equ os_SystemVariables + 0x0020
 os_PacketBase:		equ os_SystemVariables + 0x0028
-sys_timer:		equ os_SystemVariables + 0x0048
+sys_time:		equ os_SystemVariables + 0x0040
+sys_delay:		equ os_SystemVariables + 0x0048
 os_HPET_Address:	equ os_SystemVariables + 0x0050
 os_AHCI_Base:		equ os_SystemVariables + 0x0058
 os_NetworkCallback:	equ os_SystemVariables + 0x0060