github.com/jspc/eggos@v0.5.1-0.20221028160421-556c75c878a5/kernel/asm_amd64.s (about)

     1  #include "textflag.h"
     2  
     3  // copy from go_tls.h
     4  #define get_tls(r)	MOVL TLS, r
     5  #define g(r)	0(r)(TLS*1)
     6  
     7  // rt0 is the entry point of the kernel, which invokes kernel.preinit.
     8  TEXT ·rt0(SB), NOSPLIT, $0-0
     9  	// switch to new stack
    10  	MOVQ $0x80000, SP
    11  	XORQ BP, BP
    12  
    13  	// DI and SI store multiboot magic and info passed by bootloader
    14  	SUBQ $0x10, SP
    15  	MOVQ DI, 0(SP)
    16  	MOVQ SI, 8(SP)
    17  	CALL ·preinit(SB)
    18  	INT  $3
    19  
    20  	// never return
    21  
    22  // go_entry invokes _rt0_amd64_linux of the Go runtime.
    23  TEXT ·go_entry(SB), NOSPLIT, $0
    24  	SUBQ  $256, SP
    25  	PUSHQ SP
    26  	CALL  ·prepareArgs(SB)
    27  	ADDQ  $8, SP
    28  	JMP   _rt0_amd64_linux(SB)
    29  
    30  // sseInit initializes the SSE instruction set.
    31  TEXT ·sseInit(SB), NOSPLIT, $0
    32  	MOVL CR0, AX
    33  	ANDW $0xFFFB, AX
    34  	ORW  $0x2, AX
    35  	MOVL AX, CR0
    36  	MOVL CR4, AX
    37  	ORW  $3<<9, AX
    38  	MOVL AX, CR4
    39  	RET
    40  
    41  // avxInit initializes the AVX instruction set.
    42  TEXT ·avxInit(SB), NOSPLIT, $0
    43  	// enable XGETBV and XSETBV
    44  	MOVL CR4, AX
    45  	ORL  $1<<18, AX
    46  	MOVL AX, CR4
    47  
    48  	// enable avx
    49  	XORQ CX, CX
    50  	XGETBV
    51  
    52  	ORQ  $7, AX
    53  	XORQ CX, CX
    54  	XSETBV
    55  	RET
    56  
    57  // rdmsr(reg uint32) (ax, dx uint32) - Read from Model Specific Register.
    58  TEXT ·rdmsr(SB), NOSPLIT, $0-16
    59  	MOVL reg+0(FP), CX
    60  	RDMSR
    61  	MOVL AX, lo+8(FP)
    62  	MOVL DX, hi+12(FP)
    63  	RET
    64  
    65  // wrmsr(reg, lo, hi uint32) - Write to Model Specific Register.
    66  TEXT ·wrmsr(SB), NOSPLIT, $0-16
    67  	MOVL reg+0(FP), CX
    68  	MOVL lo+8(FP), AX
    69  	MOVL hi+12(FP), DX
    70  	WRMSR
    71  	RET
    72  
    73  // getg() uint64 - returns G from thread local storage of the current thread.
    74  TEXT ·getg(SB), NOSPLIT, $0-8
    75  	get_tls(CX)
    76  	MOVQ g(CX), BX
    77  	MOVQ BX, ret+0(FP)
    78  	RET
    79  
    80  // cpuid(fn, cx uint32) (ax, bx, cx, dx uint32) - CPU Identification.
    81  TEXT ·cpuid(SB), NOSPLIT, $0-24
    82  	MOVL fn+0(FP), AX
    83  	MOVL cx+4(FP), CX
    84  	CPUID
    85  	MOVL AX, eax+8(FP)
    86  	MOVL BX, ebx+12(FP)
    87  	MOVL CX, ecx+16(FP)
    88  	MOVL DX, edx+20(FP)
    89  	RET