github.com/icexin/eggos@v0.4.2-0.20220216025428-78b167e4f349/kernel/thread.s (about)

     1  #include "textflag.h"
     2  
     3  #define SYS_clone	     56
     4  #define SYS_sched_yield	 24
     5  
     6  #define tls_my 0
     7  
     8  // func swtch(old **context, _new *context)
     9  TEXT ·swtch(SB), NOSPLIT, $0-16
    10  	MOVQ old+0(FP), AX
    11  	MOVQ _new+8(FP), DX
    12  
    13  	// Save old callee-saved registers
    14  	PUSHQ BP
    15  	PUSHQ BX
    16  	PUSHQ R11
    17  	PUSHQ R12
    18  	PUSHQ R13
    19  	PUSHQ R14
    20  	PUSHQ R15
    21  
    22  	// Switch stacks
    23  	MOVQ SP, (AX)
    24  	MOVQ DX, SP
    25  
    26  	POPQ R15
    27  	POPQ R14
    28  	POPQ R13
    29  	POPQ R12
    30  	POPQ R11
    31  	POPQ BX
    32  	POPQ BP
    33  	RET
    34  
    35  // Mythread() uint64
    36  TEXT ·Mythread(SB), NOSPLIT, $0-8
    37  	MOVQ tls_my(GS), AX
    38  	MOVQ AX, ret+0(FP)
    39  	RET
    40  
    41  // ksysClone(pc, stack, flags uint64) (ax uint64) invokes SYS_clone.
    42  TEXT ·ksysClone(SB), NOSPLIT, $0-32
    43  	MOVQ $SYS_clone, AX
    44  	MOVQ pc+0(FP), R12
    45  	MOVQ stack+8(FP), SI
    46  	MOVQ flags+16(FP), DI
    47  
    48  	// clear tls
    49  	XORQ R8, R8
    50  
    51  	INT $0x80
    52  
    53  	// In parent, return.
    54  	CMPQ AX, $0
    55  	JEQ  3(PC)
    56  	MOVQ AX, ret+24(FP)
    57  	RET
    58  
    59  	NOP SP  // tell vet SP changed - stop checking offsets
    60  	JMP R12
    61  
    62  // ksysYield invokes SYS_sched_yield.
    63  TEXT ·ksysYield(SB), NOSPLIT, $0
    64  	MOVQ $SYS_sched_yield, AX
    65  	INT  $0x80
    66  	RET