/* isr stack */
/* ss:rsp (original rsp) -> rflags -> cs -> rip */

/* callee saved registers: rbx, rbp, rsp, r12, r13, r14, r15 */
/* isr saved registers: rsp, rip, rflags, cs, ss */

/* if the code will stay on same thread of execution use push/pop_caller_saved
 * else use push/pop_callee_saved with push/pop_caller_saved
 */

.set R15_OFF, 0x0
.set R14_OFF, 0x08
.set R13_OFF, 0x10
.set R12_OFF, 0x18
.set RBP_OFF, 0x20
.set RBX_OFF, 0x28
.set SEG_OFF, 0x30
.set R11_OFF, 0x38
.set R10_OFF, 0x40
.set R9_OFF, 0x48
.set R8_OFF, 0x50
.set RDI_OFF, 0x58
.set RSI_OFF, 0x60
.set RDX_OFF, 0x68
.set RCX_OFF, 0x70
.set RAX_OFF, 0x78
.set ERROR_OFF, 0x80
.set RIP_OFF, 0x88
.set CS_OFF, 0x90
.set RFLAGS_OFF, 0x98
.set RSP_OFF, 0x100
.set SS_OFF, 0x108

/* push 0x30 bytes to stack */
.macro push_callee_saved
	push %rbx
	push %rbp
	push %r12
	push %r13
	push %r14
	push %r15
.endm

/* pop 0x30 bytes from stack */
.macro pop_callee_saved
	pop %r15
	pop %r14
	pop %r13
	pop %r12
	pop %rbp
	pop %rbx
.endm

/* push 0x50 bytes to stack */
.macro push_caller_saved
	push %rax
	push %rcx
	push %rdx
	push %rsi
	push %rdi
	push %r8
	push %r9
	push %r10
	push %r11
	mov %ds, %ax
	shl $16, %rax
	mov %es, %ax
	shl $16, %rax
	mov %fs, %ax
	shl $16, %rax
	mov %gs, %ax
	push %rax
	mov $0x10, %ax
	mov %ax, %ds
	mov %ax, %ss
	mov %ax, %es
	mov %ax, %fs
	mov %ax, %gs
	mov 0x48(%rsp), %rax
.endm

/* pop 0x50 bytes from stack */
.macro pop_caller_saved
	pop %rax
	mov %ax, %gs
	shr $16, %rax
	mov %ax, %fs
	shr $16, %rax
	mov %ax, %es
	shr $16, %rax
	mov %ax, %ds
	pop %r11
	pop %r10
	pop %r9
	pop %r8
	pop %rdi
	pop %rsi
	pop %rdx
	pop %rcx
	pop %rax
.endm