1 files changed, 113 insertions, 0 deletions
diff --git a/kernel/src/scheduler/switch_process.S b/kernel/src/scheduler/switch_process.S
new file mode 100644
index 0000000..7209d37
--- /dev/null
+++ b/kernel/src/scheduler/switch_process.S
@@ -0,0 +1,113 @@
+.extern current_process
+.extern schedule
+
+.text
+
+.set RAX,	0x0
+.set RBX,	0x8
+.set RCX,	0x10
+.set RDX,	0x18
+.set RSI,	0x20
+.set RDI,	0x28
+.set RSP,	0x30
+.set RBP,	0x38
+.set R8,	0x40
+.set R9,	0x48
+.set R10,	0x50
+.set R11,	0x58
+.set R12,	0x60
+.set R13,	0x68
+.set R14,	0x70
+.set R15,	0x78
+.set RIP,	0x80
+.set RFLAGS,	0x88
+.set CR3,	0x90
+.set CS,	0x98
+.set DS,	0x9c
+.set SS,	0x100
+.set ES,	0x104
+.set FS,	0x108
+.set GS,	0x10c
+
+.macro save_regs
+	mov %rax,	RAX(%rsp)
+	mov %rbx,	RBX(%rsp)
+	mov %rax,	RAX(%rsp)
+	mov %rbx,	RBX(%rsp)
+	mov %rcx,	RCX(%rsp)
+	mov %rdx,	RDX(%rsp)
+	mov %rsi,	RSI(%rsp)
+	mov %rdi,	RDI(%rsp)
+#	mov %rsp,	RSP(%rsp)
+	mov %rbp,	RBP(%rsp)
+	mov %r8,	R8(%rsp)
+	mov %r9,	R9(%rsp)
+	mov %r10,	R10(%rsp)
+	mov %r11,	R11(%rsp)
+	mov %r12,	R12(%rsp)
+	mov %r13,	R13(%rsp)
+	mov %r14,	R14(%rsp)
+	mov %r15,	R15(%rsp)
+#	mov %rip,	RIP(%rsp)
+
+	pushfq
+	pop %rax
+	mov %rax,	RFLAGS(%rsp)
+
+#	mov %cr3,	CR3(%rsp)
+	mov %cs,	CS(%rsp)
+	mov %ds,	DS(%rsp)
+	mov %ss,	SS(%rsp)
+	mov %es,	ES(%rsp)
+	mov %fs,	FS(%rsp)
+	mov %gs,	GS(%rsp)
+.endm
+
+.macro restore_regs
+	mov RBX(%rsp),		%rbx
+	mov RAX(%rsp),		%rax
+	mov RBX(%rsp),		%rbx
+	mov RCX(%rsp),		%rcx
+	mov RDX(%rsp),		%rdx
+	mov RSI(%rsp),		%rsi
+	mov RDI(%rsp),		%rdi
+#	mov RSP(%rsp),		%rsp
+	mov RBP(%rsp),		%rbp
+	mov R8(%rsp),		%r8
+	mov R9(%rsp),		%r9
+	mov R10(%rsp),		%r10
+	mov R11(%rsp),		%r11
+	mov R12(%rsp),		%r12
+	mov R13(%rsp),		%r13
+	mov R14(%rsp),		%r14
+	mov R15(%rsp),		%r15
+#	mov RIP(%rsp),		%rip
+
+	mov RFLAGS(%rsp),	%rax
+	push %rax
+	popfq
+
+	mov RAX(%rsp),		%rax
+
+#	mov CR3(%rsp),		%cr3
+	mov CS(%rsp),		%cs
+	mov DS(%rsp),		%ds
+	mov SS(%rsp),		%ss
+	mov ES(%rsp),		%es
+	mov FS(%rsp),		%fs
+	mov GS(%rsp),		%gs
+.endm
+
+
+.global switch_process
+switch_process:
+	# save current process context
+	mov current_process, %rsp
+	save_regs
+
+	# get which process is next
+	call schedule
+
+	# restore next process context
+	mov current_process, %rsp
+	restore_regs