Bazel build

1 files changed, 55 insertions, 0 deletions

diff --git a/arch/i386/lidt.c b/arch/i386/lidt.c
new file mode 100644
index 0000000..86567f8
--- /dev/null
+++ b/arch/i386/lidt.c
@@ -0,0 +1,55 @@
+#include "idt.h"
+#include <stdint.h>
+
+struct __attribute__((packed)) Pointer {
+  uint16_t limit;
+  uint32_t base;
+};
+
+enum Type {
+  Null = 0,
+  Intr = 0x8e /* 1000 1110  32-bit interrupt */
+};
+
+struct __attribute__((packed)) Gate_t {
+  uint16_t offset_15_0;  /* segment offset low */
+  uint16_t selector;     /* code segment selector */
+  uint8_t __unused;      /* unused in protected mode */
+  uint8_t type;          /* interrupt type */
+  uint16_t offset_31_16; /* segment offset high */
+};
+/* _Static_assert(sizeof(struct Gate_t) == 8, "interrupt gate size"); */
+
+void
+Gate(struct Gate_t *entry, void (*f)(struct interrupt_frame *), uint16_t selector)
+{
+  uint32_t f_addr = (uint32_t)f;
+  entry->offset_15_0 = f_addr & 0xffff;
+  entry->offset_31_16 = (uint16_t)(f_addr >> 16) & 0xffff;
+  entry->selector = selector;
+  entry->__unused = 0;
+  entry->type = Intr;
+}
+
+static struct Gate_t interrupt_table[256] __attribute((aligned(4096)));
+
+void
+idt_install()
+{
+  int i;
+  const struct Pointer ptr = {sizeof(interrupt_table) - 1, (unsigned)&interrupt_table};
+
+  /* exceptions 0x00~0x13 */
+  for (i = 0; i <= 0x13; ++i) Gate(&interrupt_table[i], &abort_handler, 0x10);
+
+  /* irq 0x20~0x2f */
+  for (i = 0x22; i <= 0x2f; ++i) Gate(&interrupt_table[i], &abort_handler, 0x10);
+  Gate(&interrupt_table[0x20], &irq0x00, 0x10);
+  Gate(&interrupt_table[0x21], &irq0x01, 0x10);
+  Gate(&interrupt_table[0x2c], &irq0x0c, 0x10);
+
+  /* syscall 0x80 */
+  Gate(&interrupt_table[0x80], &syscall_handler, 0x10);
+
+  __asm__("lidt (%0)" : : "a"(&ptr));
+}