* in %rdi, %rsi, %rdx.
 */
.globl EXT(crosscall1)
EXT(crosscall1):
	pushq %rbx
	pushq %rbp
	pushq %r12
	pushq %r13
	pushq %r14
	pushq %r15

#if defined(_WIN64)
	movq %r8, %rdi	/* arg of setg_gcc */
	call *%rdx	/* setg_gcc */
	call *%rcx	/* fn */
#else
	movq %rdi, %rbx
	movq %rdx, %rdi	/* arg of setg_gcc */
	call *%rsi	/* setg_gcc */
	call *%rbx	/* fn */
#endif

	print("rax     ", hex(r.rax), "\n")
	print("rbx     ", hex(r.rbx), "\n")
	print("rcx     ", hex(r.rcx), "\n")
	print("rdx     ", hex(r.rdx), "\n")
	print("rdi     ", hex(r.rdi), "\n")
	print("rsi     ", hex(r.rsi), "\n")
	print("rbp     ", hex(r.rbp), "\n")
	print("rsp     ", hex(r.rsp), "\n")
	print("r8      ", hex(r.r8), "\n")
	print("r9      ", hex(r.r9), "\n")
	print("r10     ", hex(r.r10), "\n")

func (c *sigctxt) rcx() uint64 { return c.regs().rcx }
func (c *sigctxt) rdx() uint64 { return c.regs().rdx }
func (c *sigctxt) rdi() uint64 { return c.regs().rdi }
func (c *sigctxt) rsi() uint64 { return c.regs().rsi }
func (c *sigctxt) rbp() uint64 { return c.regs().rbp }
func (c *sigctxt) rsp() uint64 { return c.regs().rsp }
func (c *sigctxt) r8() uint64  { return c.regs().r8 }

	R13      uint64
	R12      uint64
	Rbp      uint64
	Rbx      uint64
	R11      uint64
	R10      uint64
	R9       uint64
	R8       uint64
	Rax      uint64
	Rcx      uint64
	Rdx      uint64
	Rsi      uint64
	Rdi      uint64
	Orig_rax uint64
	Rip      uint64
	Cs       uint64
	Eflags   uint64
	Rsp      uint64
	Ss       uint64
	Fs_base  uint64
	Gs_base  uint64
	Ds       uint64
	Es       uint64

func (c *sigctxt) rcx() uint64 { return c.regs().__gregs[_REG_RCX] }
func (c *sigctxt) rdx() uint64 { return c.regs().__gregs[_REG_RDX] }
func (c *sigctxt) rdi() uint64 { return c.regs().__gregs[_REG_RDI] }
func (c *sigctxt) rsi() uint64 { return c.regs().__gregs[_REG_RSI] }
func (c *sigctxt) rbp() uint64 { return c.regs().__gregs[_REG_RBP] }
func (c *sigctxt) rsp() uint64 { return c.regs().__gregs[_REG_RSP] }

    addl    4(%esp), %eax
    ret
'''

    private static String x64GnuAsmSource = '''
    .text
    .p2align 4,,15
.globl sumx
    .type   sumx, @function
sumx:
    leal    (%rsi,%rdi), %eax
    ret
'''

	R10L: "R10L",
	R11L: "R11L",
	R12L: "R12L",
	R13L: "R13L",
	R14L: "R14L",
	R15L: "R15L",
	RAX:  "RAX",
	RCX:  "RCX",
	RDX:  "RDX",
	RBX:  "RBX",
	RSP:  "RSP",
	RBP:  "RBP",
	RSI:  "RSI",
	RDI:  "RDI",
	R8:   "R8",
	R9:   "R9",
	R10:  "R10",
	R11:  "R11",
	R12:  "R12",
	R13:  "R13",
	R14:  "R14",
	R15:  "R15",
	IP:   "IP",
	EIP:  "EIP",
	RIP:  "RIP",

	r8          uint64
	r9          uint64
	r10         uint64
	r11         uint64
	r12         uint64
	r13         uint64
	r14         uint64
	r15         uint64
	rdi         uint64
	rsi         uint64
	rbp         uint64
	rbx         uint64
	rdx         uint64
	rax         uint64
	rcx         uint64
	rsp         uint64
	rip         uint64
	eflags      uint64
	cs          uint16

	mmst_rsrv [6]int8
}

type regxmm struct {
	xmm_reg [16]int8
}

type regs64 struct {
	rax    uint64
	rbx    uint64
	rcx    uint64
	rdx    uint64
	rdi    uint64
	rsi    uint64
	rbp    uint64
	rsp    uint64
	r8     uint64
	r9     uint64
	r10    uint64
	r11    uint64
	r12    uint64
	r13    uint64
	r14    uint64
	r15    uint64
	rip    uint64

.globl __umodti3
__umodti3:
	# specialized to u128 % u64, so verify that
	test %rcx,%rcx
	jne 1f

	# save divisor
	movq %rdx, %r8

	# reduce top 64 bits mod divisor
	movq %rsi, %rax
	xorl %edx, %edx
	divq %r8

	# reduce full 128-bit mod divisor
	# quotient fits in 64 bits because top 64 bits have been reduced < divisor.
	# (even though we only care about the remainder, divq also computes