Clear the direction flag upon entry to the kernel.

kernel/x64/boot.S

@@ -73,6 +73,9 @@ nullpage: .global nullpage
 .code32
 _start:
 __start:
+	# Clear the direction flag.
+	cld
+
 	# Initialize the stack pointer. The magic value is from kernel.cpp.
 	movl $(stack + 65536), %esp # 64 KiB, see kernel.cpp (See below also)
 

kernel/x64/interrupt.S

@@ -339,6 +339,7 @@ thread_exit_handler:
 	jmp interrupt_handler_prepare
 
 interrupt_handler_prepare:
+	cld
 	movq $1, asm_is_cpu_interrupted
 
 	pushq %r15

kernel/x64/syscall.S

@@ -24,6 +24,7 @@
 .section .text
 .type syscall_handler, @function
 syscall_handler:
+	cld
 	movl $0, errno
 
 	pushq %rbp

kernel/x86/boot.S

@@ -54,6 +54,9 @@ nullpage: .global nullpage
 .type __start, @function
 _start:
 __start:
+	# Clear the direction flag.
+	cld
+
 	# Initialize the stack pointer. The magic value is from kernel.cpp.
 	movl $(stack + 65536), %esp # 64 KiB, see kernel.cpp
 

kernel/x86/interrupt.S

@@ -339,6 +339,7 @@ thread_exit_handler:
 	jmp interrupt_handler_prepare
 
 interrupt_handler_prepare:
+	cld
 	movl $1, asm_is_cpu_interrupted
 
 	# Check if an interrupt happened while having kernel permissions.

kernel/x86/syscall.S

@@ -25,6 +25,8 @@
 .type syscall_handler, @function
 syscall_handler:
 	/* -- stack is 12 bytes from being 16-byte aligned -- */
+	cld
+
 	movl $0, errno
 
 	pushl %ebp