Read libco save and restore the on-site assembly code

x86 64 Place below 
struct coctx_t
{
    
	void *regs[ 14 ];
	size_t ss_size;
	char *ss_sp;
};
void coctx_swap(coctx_t*, coctx_t*) asm("coctx_swap");

/**  Before entering this code, there will be call Operation and stack pressing operation ,  about x86 64bit machine : %rdi, %rsi, %rdx, %rcx, %r8, %r9 ： Six registers , When the parameter is less than 7 Time ,  The parameters are put into the register from left to right : rdi, rsi, rdx, rcx, r8, r9;  When the parameter is 7 More than one time , front  6  One is the same as before ,  But the later ones start from " Right to left " Put in stack , Namely and 32 Bit assembly   So the stack should be  h <- rbp  Return value address  <- rsp l */

	leaq (%rsp),%rax        /* rsp Store the address of the return value  rax = &ra ra: rerurn address */
    movq %rax, 104(%rdi)    /*  The last row rsp The value of the register is put in rax, So at this point the parameter 1( Assuming that param1) Of regs[13] What you save is rsp Register value  */
    movq %rbx, 96(%rdi)     /* param1->regs[12] = rbx */
    movq %rcx, 88(%rdi)     /* param1->regs[11] = rcx */
    movq %rdx, 80(%rdi)     /* param1->regs[10] = rdx */
	movq 0(%rax), %rax      /* rax Store the address of the return value ,mov The instruction assigns the return value to rax register  *&ra = ra */
	movq %rax, 72(%rdi)     /* param1->regs[9] = rax */
    movq %rsi, 64(%rdi)     /* param1->regs[8] = rsi */
	movq %rdi, 56(%rdi)     /* param1->regs[7] = rdi */
    movq %rbp, 48(%rdi)     /* param1->regs[6] = rbp */
    movq %r8, 40(%rdi)					.
    movq %r9, 32(%rdi)					.
    movq %r12, 24(%rdi)					.
    movq %r13, 16(%rdi)
    movq %r14, 8(%rdi)
    movq %r15, (%rdi)       /* param1->regs[0] = r15 */
	xorq %rax, %rax         /*  XOR instruction  rax = rax ^ rax = 0 ,  Empty rax value */
                            /*  The above is used to save the current stack to the first parameter  */

                            /*  The following is used to restore the site from the second parameter  */
    movq 48(%rsi), %rbp     /*  Because recovery is the opposite of saving , So you can refer to the above analysis  */
    movq 104(%rsi), %rsp
    movq (%rsi), %r15
    movq 8(%rsi), %r14
    movq 16(%rsi), %r13
    movq 24(%rsi), %r12
    movq 32(%rsi), %r9
    movq 40(%rsi), %r8
    movq 56(%rsi), %rdi
    movq 80(%rsi), %rdx
    movq 88(%rsi), %rcx
    movq 96(%rsi), %rbx
	leaq 8(%rsp), %rsp      
                        /* rsp First, the storage is from param2->regs[13] The value taken out ,  After this operation, the rsp Address in register +8 byte   Assign a value to rsp,  here rsp It refers to the function parameter 1 to be executed ( If there is no parameter, it is equal to rbp Value ) */
	pushq 72(%rsi)      /*  take param2->regs[9] ( That is, the return value address )  Pressing stack  rsp Address  - 8*/
                        /*  The function of these two sentences is to update the return value address  */
    movq 64(%rsi), %rsi
	ret