add clock

5 files changed, 333 insertions, 4 deletions

diff --git a/kernel/source/entry.cpp b/kernel/source/entry.cpp
index efa70fd..73e79c7 100644
--- a/kernel/source/entry.cpp
+++ b/kernel/source/entry.cpp
@@ -7,6 +7,7 @@
 #include <hilbert/kernel/serial.hpp>
 #include <hilbert/kernel/input.hpp>
 #include <hilbert/kernel/panic.hpp>
+#include <hilbert/kernel/timer.hpp>
 #include <hilbert/kernel/vfile.hpp>
 #include <limine.h>
 
@@ -179,6 +180,7 @@ extern "C" [[noreturn]] void entry() {
   if (!have_initfs)
     panic(0x5f8860);
 
+  timer::init_timer();
   input::init_input();
   application::init_applications();
 
diff --git a/kernel/source/interrupts.asm b/kernel/source/interrupts.asm
index e4912ee..df8e7ce 100644
--- a/kernel/source/interrupts.asm
+++ b/kernel/source/interrupts.asm
@@ -267,6 +267,22 @@ isr_end:
 
   ret
 
+extern on_rtc_interrupt
+
+rtc_isr:
+
+  call isr_start
+
+  call on_rtc_interrupt
+
+  mov al, 0x20
+  out 0x20, al
+  out 0xa0, al
+
+  call isr_end
+
+  iretq
+
 extern on_keyboard_interrupt
 
 keyboard_isr:
@@ -343,7 +359,7 @@ load_gdt_and_idt:
   out 0x21, al
   mov al, 0x01
   out 0x21, al
-  mov al, 0xf9 ;mask all but irq 1 and 2
+  mov al, 0xf9 ;mask all but irqs 1 and 2
   out 0x21, al
 
   mov al, 0x11
@@ -354,9 +370,15 @@ load_gdt_and_idt:
   out 0xa1, al
   mov al, 0x01
   out 0xa1, al
-  mov al, 0xef ;mask all but irq 12
+  mov al, 0xee ;mask all but irqs 8 and 12
   out 0xa1, al
 
+  ;register rtc interrupt
+
+  mov rdi, 0x28
+  mov rsi, rtc_isr
+  call set_isr
+
   ;register keyboard and mouse interrupts
 
   mov rdi, 0x21
diff --git a/kernel/source/syscall.cpp b/kernel/source/syscall.cpp
index c631df1..803f7d2 100644
--- a/kernel/source/syscall.cpp
+++ b/kernel/source/syscall.cpp
@@ -4,6 +4,7 @@
 #include <hilbert/kernel/paging.hpp>
 #include <hilbert/kernel/input.hpp>
 #include <hilbert/kernel/panic.hpp>
+#include <hilbert/kernel/timer.hpp>
 #include <hilbert/kernel/vfile.hpp>
 
 namespace hilbert::kernel::syscall {
@@ -800,6 +801,29 @@ namespace hilbert::kernel::syscall {
 
   }
 
+  void sleep_syscall(
+    uint64_t &rax, uint64_t &rdi, uint64_t &rsi, uint64_t &rdx) {
+
+    uint64_t mis = rdi;
+    set_zero(rax, rdi, rsi, rdx);
+
+    auto *t = application::running_thread;
+
+    timer::register_sleeping_thread(
+      timer::current_time + mis, t);
+
+    application::yield(t->saved_state);
+
+  }
+
+  void get_time_syscall(
+    uint64_t &rax, uint64_t &rdi, uint64_t &rsi, uint64_t &rdx) {
+
+    set_zero(rax, rdi, rsi, rdx);
+    rax = timer::current_time;
+
+  }
+
   void (*handlers[])(
     uint64_t &rax, uint64_t &rdi, uint64_t &rsi, uint64_t &rdx) = {
 
@@ -827,11 +851,13 @@ namespace hilbert::kernel::syscall {
     &clear_socket_read_queue_syscall,
     &get_environment_variable_length_syscall,
     &get_environment_variable_value_syscall,
-    &set_thread_name_syscall
+    &set_thread_name_syscall,
+    &sleep_syscall,
+    &get_time_syscall
 
   };
 
-  static constexpr int max_syscall_number = 24;
+  static constexpr int max_syscall_number = 26;
 
 }
 
diff --git a/kernel/source/timer.asm b/kernel/source/timer.asm
new file mode 100644
index 0000000..d5f6f73
--- /dev/null
+++ b/kernel/source/timer.asm
@@ -0,0 +1,162 @@
+bits 64
+
+section .rodata
+
+section .text
+
+read_cmos_byte:
+;dil in = register number
+;al out = value
+;rdx and rcx are not touched
+
+  mov al, dil
+  out 0x70, al
+  in al, 0x71
+  ret
+
+global enable_rtc_interrupts
+enable_rtc_interrupts:
+
+  ;secondary status register
+  mov dil, 11
+  call read_cmos_byte
+
+  ;enable interrupts
+  or al, 0x40
+  mov cl, al
+
+  ;do cmos write
+  mov al, 11
+  out 0x70, al
+  mov al, cl
+  out 0x71, al
+
+  ret
+
+global acknowledge_rtc_interrupt
+acknowledge_rtc_interrupt:
+  mov dil, 12
+  jmp read_cmos_byte
+
+convert_bcd:
+;al in = byte (possibly bcd)
+;al out = byte (not bcd)
+;sil 0x02 = bcd
+;does not touch rdx, rcx, sil
+  test sil, 0x02
+  jz .no_convert
+
+  mov dil, al
+  and dil, 0xf0
+  and al, 0x0f
+  shr dil, 3
+  add al, dil
+  shl dil, 2
+  add al, dil
+
+.no_convert:
+  ret
+
+convert_hours:
+;al in = byte (possibly bcd and 12 hour)
+;al out = byte (not bcd or 12 hour)
+;sil 0x02 = bcd, sil 0x01 = 12 hour
+;does not touch rdx, rcx, sil
+  test sil, 0x01
+  jz convert_bcd
+
+  test al, 0x80
+  jz .am
+
+  and al, 0x7f
+  call convert_bcd
+  cmp al, 12
+  je .noon
+
+  add al, 12
+  ret
+
+.noon:
+  ret
+
+.am:
+  call convert_bcd
+  cmp al, 12
+  je .midnight
+
+  ret
+
+.midnight:
+  xor al, al
+  ret
+
+global get_time_from_rtc
+get_time_from_rtc:
+;rax out = time (see timer.cpp for encoding)
+;we assume the year is 20xx (sorry)
+
+  mov dil, 11
+  call read_cmos_byte
+
+  shr al, 1
+  not al
+  and al, 3
+  mov sil, al
+
+  xor rdx, rdx
+
+.outer_loop:
+  mov rcx, rdx
+
+.wait_for_update_loop:
+  ;status register - 0x80 is update in progress
+  mov dil, 10
+  call read_cmos_byte
+  test al, 0x80
+  jnz .wait_for_update_loop
+
+  ;years
+  mov dil, 9
+  call read_cmos_byte
+  call convert_bcd
+  mov dh, al
+
+  ;months
+  mov dil, 8
+  call read_cmos_byte
+  call convert_bcd
+  mov dl, al
+
+  shl edx, 16
+
+  ;days
+  mov dil, 7
+  call read_cmos_byte
+  call convert_bcd
+  mov dh, al
+
+  ;hours
+  mov dil, 4
+  call read_cmos_byte
+  call convert_hours
+  mov dl, al
+
+  shl rdx, 16
+
+  ;minutes
+  mov dil, 2
+  call read_cmos_byte
+  call convert_bcd
+  mov dh, al
+
+  ;seconds
+  xor dil, dil
+  call read_cmos_byte
+  call convert_bcd
+  mov dl, al
+
+  cmp rdx, rcx
+  jne .outer_loop
+
+  mov rax, rdx
+  ret
diff --git a/kernel/source/timer.cpp b/kernel/source/timer.cpp
new file mode 100644
index 0000000..d6d37d7
--- /dev/null
+++ b/kernel/source/timer.cpp
@@ -0,0 +1,117 @@
+#include <hilbert/kernel/timer.hpp>
+
+namespace hilbert::kernel::timer {
+
+  struct sleeping_thread {
+    uint64_t sleeping_until;
+    application::thread *thread;
+  };
+
+  //sorted ascending by sleeping_until
+  static utility::list<sleeping_thread> *sleeping_threads;
+
+  uint64_t current_time;
+
+  //output is
+  //   seconds     | (minutes <<  8) | (hours << 16) |
+  //  (days << 24) | ( months << 32) | (years << 40)
+  extern "C" uint64_t get_time_from_rtc();
+
+  //index is (year % 4) * 12 + month - 1;
+  //output is days from january 1st 2000 to [month] 1st [year]
+  static uint16_t month_table[] {
+       0,   31,   60,   91,  121,  152,
+     182,  213,  244,  274,  305,  335,
+     366,  397,  425,  456,  486,  517,
+     547,  578,  609,  639,  670,  700,
+     731,  762,  790,  821,  851,  882,
+     912,  943,  974, 1004, 1035, 1065,
+    1096, 1127, 1155, 1186, 1216, 1247,
+    1277, 1308, 1339, 1369, 1400, 1430
+  };
+
+  //index is (year % 4) * 12 + month - 1;
+  //output is days in that month
+  static uint8_t month_table_2[] = {
+    31, 29, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31,
+    31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31,
+    31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31,
+    31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31
+  };
+
+  void clamp(uint8_t &value, uint8_t min, uint8_t max) {
+    if (value < min)
+      value = min;
+    else if (value > max)
+      value = max;
+  }
+
+  extern "C" void enable_rtc_interrupts();
+
+  void init_timer() {
+
+    sleeping_threads = new utility::list<sleeping_thread>();
+
+    uint64_t rtc_time = get_time_from_rtc();
+
+    uint8_t   years =  rtc_time >> 40;
+    uint8_t  months = (rtc_time >> 32) & 0xff;
+    uint8_t    days = (rtc_time >> 24) & 0xff;
+    uint8_t   hours = (rtc_time >> 16) & 0xff;
+    uint8_t minutes = (rtc_time >>  8) & 0xff;
+    uint8_t seconds =  rtc_time        & 0xff;
+
+    uint8_t month_table_index =
+      (years % 4) * 12 + months - 1;
+
+    clamp(  years, 0, 99);
+    clamp( months, 1, 12);
+    clamp(   days, 1, month_table_2[month_table_index]);
+    clamp(  hours, 0, 23);
+    clamp(minutes, 0, 59);
+    clamp(seconds, 0, 59);
+
+    current_time  = 1461 * (years / 4);
+    current_time += month_table[month_table_index];
+    current_time += days - 1;
+    current_time *= 86400;
+    current_time += hours * 3600;
+    current_time += minutes * 60;
+    current_time += seconds;
+    current_time *= 1024;
+
+    enable_rtc_interrupts();
+
+  }
+
+  void register_sleeping_thread(
+    uint64_t sleeping_until, application::thread *thread) {
+
+    auto *after = sleeping_threads->first;
+    while (after && after->value.sleeping_until < sleeping_until)
+      after = after->next;
+
+    sleeping_threads->insert_before(
+      { .sleeping_until = sleeping_until, .thread = thread }, after);
+
+  }
+
+  extern "C" void acknowledge_rtc_interrupt();
+
+  extern "C" void on_rtc_interrupt() {
+
+    ++current_time;
+
+    while (sleeping_threads->first &&
+           sleeping_threads->first->value.sleeping_until <=
+             current_time) {
+      application::paused_threads->insert(
+        sleeping_threads->first->value.thread);
+      sleeping_threads->remove(sleeping_threads->first);
+    }
+
+    acknowledge_rtc_interrupt();
+
+  }
+
+}