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Diffstat (limited to 'src/kernel/interact.asm')
| -rw-r--r-- | src/kernel/interact.asm | 194 |
1 files changed, 0 insertions, 194 deletions
diff --git a/src/kernel/interact.asm b/src/kernel/interact.asm deleted file mode 100644 index 00cdbe0..0000000 --- a/src/kernel/interact.asm +++ /dev/null @@ -1,194 +0,0 @@ -; Protected Mode BIOS Call Functionality v2.0 - by Napalm -; License: http://creativecommons.org/licenses/by-sa/2.0/uk/ -[bits 32] - -global int32, _int32 - -struc regs16_t - .di resw 1 - .si resw 1 - .bp resw 1 - .sp resw 1 - .bx resw 1 - .dx resw 1 - .cx resw 1 - .ax resw 1 - .gs resw 1 - .fs resw 1 - .es resw 1 - .ds resw 1 - .ef resw 1 -endstruc - -%define INT32_BASE 0x7C00 -%define REBASE(x) (((x) - reloc) + INT32_BASE) -%define GDTENTRY(x) ((x) << 3) -%define CODE32 GDTENTRY(1) ; 0x08 -%define DATA32 GDTENTRY(2) ; 0x10 -%define CODE16 GDTENTRY(3) ; 0x18 -%define DATA16 GDTENTRY(4) ; 0x20 -%define STACK16 (INT32_BASE - regs16_t_size) - -section .text - int32: use32 ; by Napalm - _int32: - ;cli ; disable interrupts - pusha ; save register state to 32bit stack - mov esi, reloc ; set source to code below - mov edi, INT32_BASE ; set destination to new base address - mov ecx, (int32_end - reloc) ; set copy size to our codes size - cld ; clear direction flag (so we copy forward) - rep movsb ; do the actual copy (relocate code to low 16bit space) - jmp INT32_BASE ; jump to new code location - reloc: use32 ; by Napalm - mov [REBASE(stack32_ptr)], esp ; save 32bit stack pointer - sidt [REBASE(idt32_ptr)] ; save 32bit idt pointer - sgdt [REBASE(gdt32_ptr)] ; save 32bit gdt pointer - lgdt [REBASE(gdt16_ptr)] ; load 16bit gdt pointer - lea esi, [esp+0x24] ; set position of intnum on 32bit stack - lodsd ; read intnum into eax - mov [REBASE(ib)], al ; set intrrupt immediate byte from our arguments - mov esi, [esi] ; read regs pointer in esi as source - mov edi, STACK16 ; set destination to 16bit stack - mov ecx, regs16_t_size ; set copy size to our struct size - mov esp, edi ; save destination to as 16bit stack offset - rep movsb ; do the actual copy (32bit stack to 16bit stack) - jmp word CODE16:REBASE(p_mode16) ; switch to 16bit selector (16bit protected mode) - p_mode16: use16 - mov ax, DATA16 ; get our 16bit data selector - mov ds, ax ; set ds to 16bit selector - mov es, ax ; set es to 16bit selector - mov fs, ax ; set fs to 16bit selector - mov gs, ax ; set gs to 16bit selector - mov ss, ax ; set ss to 16bit selector - mov eax, cr0 ; get cr0 so we can modify it - and al, ~0x01 ; mask off PE bit to turn off protected mode - mov cr0, eax ; set cr0 to result - jmp word 0x0000:REBASE(r_mode16) ; finally set cs:ip to enter real-mode - r_mode16: use16 - xor ax, ax ; set ax to zero - mov ds, ax ; set ds so we can access idt16 - mov ss, ax ; set ss so they the stack is valid - lidt [REBASE(idt16_ptr)] ; load 16bit idt - mov bx, 0x0870 ; master 8 and slave 112 - call resetpic ; set pic's the to real-mode settings - popa ; load general purpose registers from 16bit stack - pop gs ; load gs from 16bit stack - pop fs ; load fs from 16bit stack - pop es ; load es from 16bit stack - pop ds ; load ds from 16bit stack - ;sti ; enable interrupts - db 0xCD ; opcode of INT instruction with immediate byte - ib: db 0x00 - ;cli ; disable interrupts - xor sp, sp ; zero sp so we can reuse it - mov ss, sp ; set ss so the stack is valid - mov sp, INT32_BASE ; set correct stack position so we can copy back - pushf ; save eflags to 16bit stack - push ds ; save ds to 16bit stack - push es ; save es to 16bit stack - push fs ; save fs to 16bit stack - push gs ; save gs to 16bit stack - pusha ; save general purpose registers to 16bit stack - mov bx, 0x2028 ; master 32 and slave 40 - call resetpic ; restore the pic's to protected mode settings - mov eax, cr0 ; get cr0 so we can modify it - inc eax ; set PE bit to turn on protected mode - mov cr0, eax ; set cr0 to result - jmp dword CODE32:REBASE(p_mode32) ; switch to 32bit selector (32bit protected mode) - p_mode32: use32 - mov ax, DATA32 ; get our 32bit data selector - mov ds, ax ; reset ds selector - mov es, ax ; reset es selector - mov fs, ax ; reset fs selector - mov gs, ax ; reset gs selector - mov ss, ax ; reset ss selector - lgdt [REBASE(gdt32_ptr)] ; restore 32bit gdt pointer - lidt [REBASE(idt32_ptr)] ; restore 32bit idt pointer - mov esp, [REBASE(stack32_ptr)] ; restore 32bit stack pointer - mov esi, STACK16 ; set copy source to 16bit stack - lea edi, [esp+0x28] ; set position of regs pointer on 32bit stack - mov edi, [edi] ; use regs pointer in edi as copy destination - mov ecx, regs16_t_size ; set copy size to our struct size - cld ; clear direction flag (so we copy forward) - rep movsb ; do the actual copy (16bit stack to 32bit stack) - popa ; restore registers - ;sti ; enable interrupts - ret ; return to caller - - resetpic: ; reset's 8259 master and slave pic vectors - push ax ; expects bh = master vector, bl = slave vector - mov al, 0x11 ; 0x11 = ICW1_INIT | ICW1_ICW4 - out 0x20, al ; send ICW1 to master pic - out 0xA0, al ; send ICW1 to slave pic - mov al, bh ; get master pic vector param - out 0x21, al ; send ICW2 aka vector to master pic - mov al, bl ; get slave pic vector param - out 0xA1, al ; send ICW2 aka vector to slave pic - mov al, 0x04 ; 0x04 = set slave to IRQ2 - out 0x21, al ; send ICW3 to master pic - shr al, 1 ; 0x02 = tell slave its on IRQ2 of master - out 0xA1, al ; send ICW3 to slave pic - shr al, 1 ; 0x01 = ICW4_8086 - out 0x21, al ; send ICW4 to master pic - out 0xA1, al ; send ICW4 to slave pic - pop ax ; restore ax from stack - ret ; return to caller - - stack32_ptr: ; address in 32bit stack after we - dd 0x00000000 ; save all general purpose registers - - idt32_ptr: ; IDT table pointer for 32bit access - dw 0x0000 ; table limit (size) - dd 0x00000000 ; table base address - - gdt32_ptr: ; GDT table pointer for 32bit access - dw 0x0000 ; table limit (size) - dd 0x00000000 ; table base address - - idt16_ptr: ; IDT table pointer for 16bit access - dw 0x03FF ; table limit (size) - dd 0x00000000 ; table base address - - gdt16_base: ; GDT descriptor table - .null: ; 0x00 - null segment descriptor - dd 0x00000000 ; must be left zero'd - dd 0x00000000 ; must be left zero'd - - .code32: ; 0x01 - 32bit code segment descriptor 0xFFFFFFFF - dw 0xFFFF ; limit 0:15 - dw 0x0000 ; base 0:15 - db 0x00 ; base 16:23 - db 0x9A ; present, iopl/0, code, execute/read - db 0xCF ; 4Kbyte granularity, 32bit selector; limit 16:19 - db 0x00 ; base 24:31 - - .data32: ; 0x02 - 32bit data segment descriptor 0xFFFFFFFF - dw 0xFFFF ; limit 0:15 - dw 0x0000 ; base 0:15 - db 0x00 ; base 16:23 - db 0x92 ; present, iopl/0, data, read/write - db 0xCF ; 4Kbyte granularity, 32bit selector; limit 16:19 - db 0x00 ; base 24:31 - - .code16: ; 0x03 - 16bit code segment descriptor 0x000FFFFF - dw 0xFFFF ; limit 0:15 - dw 0x0000 ; base 0:15 - db 0x00 ; base 16:23 - db 0x9A ; present, iopl/0, code, execute/read - db 0x0F ; 1Byte granularity, 16bit selector; limit 16:19 - db 0x00 ; base 24:31 - - .data16: ; 0x04 - 16bit data segment descriptor 0x000FFFFF - dw 0xFFFF ; limit 0:15 - dw 0x0000 ; base 0:15 - db 0x00 ; base 16:23 - db 0x92 ; present, iopl/0, data, read/write - db 0x0F ; 1Byte granularity, 16bit selector; limit 16:19 - db 0x00 ; base 24:31 - - gdt16_ptr: ; GDT table pointer for 16bit access - dw gdt16_ptr - gdt16_base - 1 ; table limit (size) - dd gdt16_base ; table base address - - int32_end: ; end marker (so we can copy the code)
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