Kernel/x86 - Cleaning up dead code

[tpg/acess2.git] / Kernel / arch / x86_64 / start64.asm

diff --git a/Kernel/arch/x86_64/start64.asm b/Kernel/arch/x86_64/start64.asm
index e69de29..b63b63a 100644 (file)
--- a/Kernel/arch/x86_64/start64.asm
+++ b/Kernel/arch/x86_64/start64.asm
@@ -0,0 +1,146 @@
+;
+; Acess2 x86_64 Port
+;
+%include "arch/x86_64/include/common.inc.asm"
+[bits 64]
+;KERNEL_BASE   equ     0xFFFF800000000000
+KERNEL_BASE    equ     0xFFFFFFFF80000000
+
+[extern kmain]
+
+[extern gMultibootPtr]
+[extern gMultibootMagic]
+
+[section .text]
+[global start64]
+start64:
+       ; Load Registers
+       mov ax, 0x10
+       mov ds, ax
+       mov es, ax
+       mov fs, ax
+       mov gs, ax
+       
+       ; Go to high memory
+       mov rax, start64.himem
+       jmp rax
+.himem:
+       
+       xor rax, rax
+       mov dr0, rax    ; Set CPU0
+       
+       ; Clear the screen
+       mov rax, 0x1F201F201F201F20     ; Set the screen to White on blue, space (4 characters)
+       mov edi, 0xB8000
+       mov ecx, 80*25*2/8
+       rep stosq
+       
+       ; Set kernel stack
+       mov rsp, 0xFFFFA00000000000 + INITIAL_KSTACK_SIZE*0x1000
+       
+       ; Call main
+       mov edi, [gMultibootMagic - KERNEL_BASE]
+       mov esi, [gMultibootPtr - KERNEL_BASE]
+       call kmain
+       
+       cli
+.hlt:
+       hlt
+       jmp .hlt
+
+[global GetCPUNum]
+GetCPUNum:
+       xor rax, rax
+       str ax
+       sub ax, 0x38    ; TSS Base
+       shr ax, 4       ; One 16-byte TSS per CPU
+       ret
+
+KSTACK_USERSTATE_SIZE  equ     (5+2+16+2)*8    ; IRET, ErrorNum, ErrorCode, GPRs, FS&GS
+[global Proc_ReturnToUser]
+Proc_ReturnToUser:
+       ; RDI - Handler
+       ; RSI - Kernel Stack
+       ; RDX - Signal num
+       
+       ;
+       ; NOTE: This can cause corruption if the signal happens while the user
+       ;       has called a kernel operation.
+       ; Good thing this can only be called on a user fault.
+       ;
+
+       xchg bx, bx     
+       ; Get and alter User SP
+       mov rcx, [rsi-0x20]     ; Get user SP
+       xor eax, eax
+       mov [rcx-16], rax
+       sub rcx, 16
+       
+       ; Drop down to user mode
+       cli
+       mov rsp, rcx    ; Set SP
+       mov rcx, rdi    ; SYSRET IP
+       
+       mov rdi, rdx    ; Argument for handler
+       mov r11, 0x202  ; RFlags
+       db 0x48
+       sysret
+
+; int CallWithArgArray(void *Ptr, int NArgs, Uint *Args)
+; Call a function passing the array as arguments
+[global CallWithArgArray]
+CallWithArgArray:
+       push rbp
+       mov rbp, rsp
+       push r10
+       push r11
+       
+       mov [rbp+2*8], rdi      ; Save Ptr to stack
+       
+       mov r11, rsi    ; NArgs
+       mov r10, rdx    ; Args
+
+       ; Arg 1: RDI
+       mov rdi, [r10]
+       add r10, 8
+       dec r11
+       jz .call
+       ; Arg 2: RSI
+       mov rsi, [r10]
+       add r10, 8
+       dec r11
+       jz .call
+       ; Arg 3: RDX
+       mov rdx, [r10]
+       add r10, 8
+       dec r11
+       jz .call
+       ; Arg 4: RCX
+       mov rcx, [r10]
+       add r10, 8
+       dec r11
+       jz .call
+       ; Arg 5: R8
+       mov r8, [r10]
+       add r10, 8
+       dec r11
+       jz .call
+       ; Arg 6: R9
+       mov r9, [r10]
+       add r10, 8
+       dec r11
+       jz .call
+       ; No support for more
+
+.call:
+       mov rax, [rbp+2*8]      ; Ptr
+       call rax
+       
+       pop r11
+       pop r10
+       
+       lea rsp, [rbp]
+       pop rbp
+       ret
+
+; vim: ft=nasm