[mubios] Add switching and return paths between real-mode interrupts and protected-mode C services.

Signed-off-by: Richard Qin <richard.qin.x@gmail.com>

1 files changed, 63 insertions, 283 deletions

diff --git a/mubios/arch/interrupt.S b/mubios/arch/interrupt.S
index 88ccfbf..0822b1a 100644
--- a/mubios/arch/interrupt.S
+++ b/mubios/arch/interrupt.S
@@ -6,31 +6,21 @@
 #
 # RCC-Project is free software; you can redistribute it and/or modify it under
 # the terms of the GNU General Public License as published by the Free
-# Software Foundation; either version 3 of the License, or (at your option) any
-# later version.
+# Software Foundation; either version 3 of the License, or (at your option)
+# any later version.
 #
-# RCC-Project is distributed in the hope that it will be useful, but WITHOUT ANY
-# WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR
-# A PARTICULAR PURPOSE.  See the GNU General Public License for more details.
-#
-# You should have received a copy of the GNU General Public License along with
-# RCC-Project; see the file COPYING.  If not see
-# <http://www.gnu.org/licenses/>.
+# RCC-Project is distributed in the hope that it will be useful, but WITHOUT
+# ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+# FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
+# more details.
 
 	.intel_syntax noprefix
 	.code16
 
-	.equ ATA_DATA,         0x1F0
-	.equ ATA_SECTOR_COUNT, 0x1F2
-	.equ ATA_LBA_LOW,      0x1F3
-	.equ ATA_LBA_MID,      0x1F4
-	.equ ATA_LBA_HIGH,     0x1F5
-	.equ ATA_DRIVE,        0x1F6
-	.equ ATA_STATUS,       0x1F7
-	.equ ATA_COMMAND,      0x1F7
-
 	.section .text16.irq, "ax"
 
+	.extern enter_protected_service
+
 	.global int1a_entry
 	.type int1a_entry, @function
 
@@ -58,268 +48,58 @@ int1a_entry:
 int1a_return:
 	iret
 
-	.global int10_entry
-	.type int10_entry, @function
-
-int10_entry:
-	cmp ah, 0x0E
-	jne int10_return
-
-	push bp
-	mov bp, sp
-
-	push ax
-	push bx
-	push dx
-	push si
-	push di
-	push ds
-	push es
-
-	xor ax, ax
-	mov ds, ax
-
-	mov ax, 0xB800
-	mov es, ax
-
-	mov si, 0x0050
-	mov dx, word ptr [si]
-
-	mov al, byte ptr [bp - 2]
-	mov bl, byte ptr [bp - 4]
-
-	cmp al, 0x0D
-	je int10_carriage_return
-
-	cmp al, 0x0A
-	je int10_line_feed
-
-	cmp al, 0x08
-	je int10_backspace
-
-	mov di, dx
-	shl di, 1
-	mov ah, bl
-	mov word ptr es:[di], ax
-	inc dx
-	jmp int10_store_cursor
-
-	
-int10_carriage_return:
-	mov ax, dx
-	mov si, 80
-	xor dx, dx
-	div si
-	mul si
-	mov dx, ax
-	jmp int10_store_cursor
-
-int10_line_feed:
-	add dx, 80
-	jmp int10_store_cursor
-
-int10_backspace:
-	cmp dx, 0
-	je int10_store_cursor
-
-	dec dx
-	mov di, dx
-	shl di, 1
-	mov al, 0x20
-	mov ah, bl
-	mov word ptr es:[di], ax
-
-int10_store_cursor:
-	cmp dx, 2000
-	jb int10_save_cursor
-
-	xor dx, dx
-
-int10_save_cursor:
-	mov word ptr [0x0050], dx
-
-	pop es
-	pop ds
-	pop di
-	pop si
-	pop dx
-	pop bx
-	pop ax
-	pop bp
-
-int10_return:
-	iret
-
-	.global int13_entry
-	.type int13_entry, @function
-
-int13_entry:
-	cmp ah, 0x42
-	je int13_extended_read
-	
-	cmp ah, 0x41
-	jne int13_return
-
-	push bp
-	mov bp, sp
-
-	cmp bx, 0x55AA
-	jne int13_fail
-
-	mov bx, 0xAA55
-	mov cx, 0x0001
-	mov ax, 0x3000
-
-	# Clear CF in the FLAGS saved by INT.
-	and word ptr [bp + 6], 0xFFFE
-
-	pop bp
-	iret
-
-int13_fail:
-	mov ah, 0x01
-
-	# Set CF in the FLAGS saved by INT.
-	or word ptr [bp + 6], 0x0001
-
-	pop bp
-	iret
-
-int13_return:
-	push bp
-	mov bp, sp
-
-	mov ah, 0x01
-
-	# Set CF in the FLAGS saved by INT.
-	or word ptr [bp + 6], 0x0001
-
-	pop bp
-	iret
-int13_extended_read:
-	push bp
-	mov bp, sp
-
-	push bx
-	push cx
-	push dx
-	push si
-	push di
-	push ds
-	push es
-
-	# DAP size must be 0x10.
-	cmp byte ptr [si], 0x10
-	jne int13_extended_fail
-
-	# This step supports exactly one sector.
-	cmp word ptr [si + 2], 1
-	jne int13_extended_fail
-
-	# Reject LBA values above 28 bits.
-	mov ax, word ptr [si + 12]
-	or ax, word ptr [si + 14]
-	jnz int13_extended_fail
-
-	mov ax, word ptr [si + 10]
-	test ax, 0xF000
-	jnz int13_extended_fail
-
-	# Load DAP buffer ES:DI.
-	mov di, word ptr [si + 4]
-	mov ax, word ptr [si + 6]
-	mov es, ax
-
-	cld
-
-	# Select ATA drive from DL.
-	mov al, 0xE0
-	test dl, 1
-	jz int13_drive_selected
-
-	or al, 0x10
-
-int13_drive_selected:
-	mov dx, ATA_DRIVE
-	out dx, al
-
-	# 400 ns delay.
-	mov dx, ATA_STATUS
-	in al, dx
-	in al, dx
-	in al, dx
-	in al, dx
-
-	# Sector count = 1.
-	mov dx, ATA_SECTOR_COUNT
-	mov al, 1
-	out dx, al
-
-	# LBA byte 0.
-	mov ax, word ptr [si + 8]
-	mov dx, ATA_LBA_LOW
-	out dx, al
-
-	# LBA byte 1.
-	mov al, ah
-	mov dx, ATA_LBA_MID
-	out dx, al
-
-	# LBA byte 2.
-	mov ax, word ptr [si + 10]
-	mov dx, ATA_LBA_HIGH
-	out dx, al
-
-	# READ SECTORS command.
-	mov dx, ATA_COMMAND
-	mov al, 0x20
-	out dx, al
-
-int13_wait_data:
-	mov dx, ATA_STATUS
-	in al, dx
-
-	test al, 0x80
-	jnz int13_wait_data
-
-	test al, 0x01
-	jnz int13_extended_fail
-
-	test al, 0x08
-	jz int13_wait_data
-
-	# Read one 512-byte sector.
-	mov dx, ATA_DATA
-	mov cx, 256
-	rep insw
-
-	# Clear CF in the saved FLAGS.
-	and word ptr [bp + 6], 0xFFFE
-
-	pop es
-	pop ds
-	pop di
-	pop si
-	pop dx
-	pop cx
-	pop bx
-	pop bp
-
-	xor ax, ax
-	iret
-
-int13_extended_fail:
-	# Set CF in the saved FLAGS.
-	or word ptr [bp + 6], 0x0001
-
-	pop es
-	pop ds
-	pop di
-	pop si
-	pop dx
-	pop cx
-	pop bx
-	pop bp
-
-	mov ax, 0x0100
-	iret
+	.macro BIOS_SERVICE_ENTRY name, vector
+	.global \name
+	.type \name, @function
+
+\name:
+		# Build struct bios_regs on the interrupted real-mode stack.
+		push 0
+		push es
+		push ds
+		push bp
+		push di
+		push si
+		push dx
+		push cx
+		push bx
+		push ax
+
+		mov bp, sp
+		mov ax, word ptr [bp + 24]
+		mov word ptr [bp + 18], ax
+
+		# ESI = linear address of struct bios_regs.
+		movzx esi, sp
+		xor eax, eax
+		mov ax, ss
+		shl eax, 4
+		add esi, eax
+
+		# EBP = original SS:SP return point, packed as SS:SP.
+		movzx ebp, sp
+		sub ebp, 2
+		xor eax, eax
+		mov ax, ss
+		shl eax, 16
+		or ebp, eax
+
+		mov edi, \vector
+		call enter_protected_service
+
+		# Restore the context modified by the C service.
+		pop ax
+		pop bx
+		pop cx
+		pop dx
+		pop si
+		pop di
+		pop bp
+		pop ds
+		pop es
+		add sp, 2
+		iret
+	.endm
+
+	BIOS_SERVICE_ENTRY int10_entry, 0x10
+	BIOS_SERVICE_ENTRY int13_entry, 0x13