// Rom layout and bios assembler to C interface.
//
-// Copyright (C) 2008 Kevin O'Connor <kevin@koconnor.net>
+// Copyright (C) 2008,2009 Kevin O'Connor <kevin@koconnor.net>
// Copyright (C) 2002 MandrakeSoft S.A.
//
-// This file may be distributed under the terms of the GNU GPLv3 license.
-
-#include "config.h" // CONFIG_*
-#include "ioport.h" // PORT_A20
-#include "bregs.h" // CR0_*
-#include "../out/asm-offsets.h" // BREGS_*
+// This file may be distributed under the terms of the GNU LGPLv3 license.
/****************************************************************
****************************************************************/
.code16gcc
-.include "out/blob.16.s"
-
-
-/****************************************************************
- * Entry macros
- ****************************************************************/
-
- // Call a C function - this does the minimal work necessary to
- // call into C. It sets up %ds, backs up %es, and backs up
- // those registers that are call clobbered by the C compiler.
- .macro ENTRY cfunc
- cld
- pushl %eax // Save registers clobbered by C code
- pushl %ecx
- pushl %edx
- pushw %es
- pushw %ds
- movw %ss, %ax // Move %ss to %ds
- movw %ax, %ds
- pushl %esp // Backup %esp, then clear high bits
- movzwl %sp, %esp
- calll \cfunc
- popl %esp // Restore %esp (including high bits)
- popw %ds // Restore registers saved above
- popw %es
- popl %edx
- popl %ecx
- popl %eax
- .endm
-
- // Call a C function with current register list as an
- // argument. This backs up the registers and sets %eax
- // to point to the backup. On return, the registers are
- // restored from the structure.
- .macro ENTRY_ARG cfunc
- cld
- pushl %eax // Save registers (matches struct bregs)
- pushl %ecx
- pushl %edx
- pushl %ebx
- pushl %esi
- pushl %edi
- pushw %es
- pushw %ds
- movw %ss, %ax // Move %ss to %ds
- movw %ax, %ds
- movl %esp, %ebx // Backup %esp, then zero high bits
- movzwl %sp, %esp
- movl %esp, %eax // First arg is pointer to struct bregs
- calll \cfunc
- movl %ebx, %esp // Restore %esp (including high bits)
- popw %ds // Restore registers (from struct bregs)
- popw %es
- popl %edi
- popl %esi
- popl %ebx
- popl %edx
- popl %ecx
- popl %eax
- .endm
-
- // As above, but don't mangle %esp
- .macro ENTRY_ARG_ESP cfunc
- cld
- pushl %eax // Save registers (matches struct bregs)
- pushl %ecx
- pushl %edx
- pushl %ebx
- pushl %esi
- pushl %edi
- pushw %es
- pushw %ds
- movw %ss, %ax // Move %ss to %ds
- movw %ax, %ds
- movl %esp, %eax // First arg is pointer to struct bregs
- calll \cfunc
- popw %ds // Restore registers (from struct bregs)
- popw %es
- popl %edi
- popl %esi
- popl %ebx
- popl %edx
- popl %ecx
- popl %eax
- .endm
-
- // Macro to reset the 16bit stack
- // Clobbers %ax
- .macro RESET_STACK
- xorw %ax, %ax
- movw %ax, %ss
- movl $ BUILD_STACK_ADDR , %esp
- cld
- .endm
-
- // Specify a location in the fixed part of bios area.
- .macro ORG addr
- .section .text.fixed.addr
- .org \addr - BUILD_START_FIXED
- .endm
-
-
-/****************************************************************
- * POST handler
- ****************************************************************/
-
- ORG 0xe05b
-post16:
- // enable cache
- movl %cr0, %eax
- andl $~(CR0_CD|CR0_NW), %eax
- movl %eax, %cr0
-
- // init the stack pointer
- RESET_STACK
+.include "out/ccode.16.s"
- pushl $_code32__start
-
- // Fall through to transition32 function below
+#include "config.h" // CONFIG_*
+#include "ioport.h" // PORT_A20
+#include "bregs.h" // CR0_*
+#include "cmos.h" // CMOS_RESET_CODE
+#include "../out/asm-offsets.h" // BREGS_*
+#include "entryfuncs.S" // ENTRY_*
/****************************************************************
****************************************************************/
// Place CPU into 32bit mode from 16bit mode.
-// Clobbers: %eax, flags, stack registers, cr0, idt/gdt
+// Clobbers: flags, segment registers, cr0, idt/gdt
+ DECLFUNC transition32
transition32:
- // Disable irqs
+ pushl %eax
+
+ // Disable irqs (and clear direction flag)
cli
+ cld
+
+ // Disable nmi
+ movl $CMOS_RESET_CODE|NMI_DISABLE_BIT, %eax
+ outb %al, $PORT_CMOS_INDEX
+ inb $PORT_CMOS_DATA, %al
// enable a20
inb $PORT_A20, %al
outb %al, $PORT_A20
// Set segment descriptors
- lidt %cs:pmode_IDT_info
- lgdt %cs:rombios32_gdt_48
+ lidtw %cs:pmode_IDT_info
+ lgdtw %cs:rombios32_gdt_48
// Enable protected mode
movl %cr0, %eax
orl $CR0_PE, %eax
movl %eax, %cr0
- // start protected mode code
+ // start 32bit protected mode code
ljmpl $SEG32_MODE32_CS, $(BUILD_BIOS_ADDR + 1f)
.code32
movw %ax, %ds
movw %ax, %es
movw %ax, %ss
- xorl %eax, %eax
movw %ax, %fs
movw %ax, %gs
+ popl %eax
retl
// Call a 16bit function from 32bit mode.
// %eax = address of struct bregs
-// Clobbers: all gp registers, flags, stack registers, cr0, idt/gdt
- .global __call16_from32
+// Clobbers: %e[bcd]x, %e[ds]i, flags, segment registers, idt/gdt
+ DECLFUNC __call16_from32
+ .global __call16big_from32
__call16_from32:
pushl %eax
// restore data segment limits to 0xffff
- movw $SEG32_MODE16_DS, %ax
+ movl $SEG32_MODE16_DS, %eax
movw %ax, %ds
movw %ax, %es
movw %ax, %ss
movw %ax, %fs
movw %ax, %gs
+#if CONFIG_DISABLE_A20
// disable a20
inb $PORT_A20, %al
andb $~A20_ENABLE_BIT, %al
outb %al, $PORT_A20
+#endif
// Jump to 16bit mode
ljmpw $SEG32_MODE16_CS, $1f
+__call16big_from32:
+ pushl %eax
+
+ movl $SEG32_MODE16BIG_DS, %eax
+ movw %ax, %ds
+ movw %ax, %es
+ movw %ax, %ss
+ movw %ax, %fs
+ movw %ax, %gs
+
+ ljmpl $SEG32_MODE16BIG_CS, $(BUILD_BIOS_ADDR + 1f)
+
.code16gcc
1:
// Disable protected mode
2:
// restore IDT to normal real-mode defaults
- lidt %cs:rmode_IDT_info
+ lidtw %cs:rmode_IDT_info
// Clear segment registers
xorw %ax, %ax
popl %eax
- // Set __call16 return address to be transition32
- pushl $transition32
+ // Make call.
+ calll __call16
- // Fall through to __call16
+ // Return via transition32
+ jmp transition32
// Call a 16bit function from 16bit mode with a specified cpu register state
// %eax = address of struct bregs
-// Clobbers: all gp registers, es
- .global __call16
+// Clobbers: %e[bcd]x, %e[ds]i, flags
+ DECLFUNC __call16
__call16:
- // Save eax
+ // Save %eax, %ebp
+ pushl %ebp
pushl %eax
// Setup for iretw call
- pushw $SEG_BIOS
+ pushw %cs
pushw $1f // return point
pushw BREGS_flags(%eax) // flags
pushl BREGS_ip(%eax) // CS:IP
// Load calling registers.
movl BREGS_edi(%eax), %edi
movl BREGS_esi(%eax), %esi
+ movl BREGS_ebp(%eax), %ebp
movl BREGS_ebx(%eax), %ebx
movl BREGS_edx(%eax), %edx
movl BREGS_ecx(%eax), %ecx
movw %es, BREGS_es(%eax)
movl %edi, BREGS_edi(%eax)
movl %esi, BREGS_esi(%eax)
+ movl %ebp, BREGS_ebp(%eax)
movl %ebx, BREGS_ebx(%eax)
movl %edx, BREGS_edx(%eax)
- // Remove %eax
+ // Remove %eax, restore %ebp
popl %eax
+ popl %ebp
+
+ retl
+
+// IRQ trampolines
+ .macro IRQ_TRAMPOLINE num
+ DECLFUNC irq_trampoline_0x\num
+ irq_trampoline_0x\num :
+ int $0x\num
+ lretw
+ .endm
+
+ IRQ_TRAMPOLINE 10
+ IRQ_TRAMPOLINE 13
+ IRQ_TRAMPOLINE 15
+ IRQ_TRAMPOLINE 16
+ IRQ_TRAMPOLINE 18
+ IRQ_TRAMPOLINE 19
+
+/****************************************************************
+ * POST entry point
+ ****************************************************************/
+
+ DECLFUNC entry_post
+entry_post:
+ // Enable cache
+ movl %cr0, %eax
+ andl $~(CR0_CD|CR0_NW), %eax
+ movl %eax, %cr0
+
+ // Disable interrupts
+ cli
cld
- retl
+ // Check for restart indicator.
+ movl $CMOS_RESET_CODE|NMI_DISABLE_BIT, %eax
+ outb %al, $PORT_CMOS_INDEX
+ inb $PORT_CMOS_DATA, %al
+ cmpb $0x0, %al
+ jnz 1f
+
+ // Normal entry point
+ ENTRY_INTO32 _start
+
+ // Entry point when a post call looks like a resume.
+1:
+ // Save old shutdown status.
+ movl %eax, %ebx
+
+ // Clear shutdown status register.
+ movl $CMOS_RESET_CODE|NMI_DISABLE_BIT, %eax
+ outb %al, $PORT_CMOS_INDEX
+ xorl %eax, %eax
+ outb %al, $PORT_CMOS_DATA
+
+ // Use a stack in EBDA
+ movw $SEG_BDA, %ax
+ movw %ax, %ds
+ movw BDA_ebda_seg, %ax
+
+ cmpw $EBDA_SEGMENT_START, %ax
+ jle 2f
+ // EBDA segment doesn't look valid - use startup value.
+ movw $EBDA_SEGMENT_START, %ax
+
+2: movw %ax, %ds
+ movw %ax, %ss
+ movl $EBDA_OFFSET_TOP_STACK, %esp
+
+ // Call handler.
+ movl %ebx, %eax
+ jmp handle_resume
-// APM trampolines
- .global apm16protected_entry
+/****************************************************************
+ * Misc. entry points.
+ ****************************************************************/
+
+// PnP entry points
+ DECLFUNC entry_pnp_real
+ .global entry_pnp_prot
+entry_pnp_prot:
+ pushl %esp
+ jmp 1f
+entry_pnp_real:
+ pushl %esp // Backup %esp, then clear high bits
+ movzwl %sp, %esp
+1:
+ pushfl // Save registers clobbered by C code
+ pushl %eax
+ pushl %ecx
+ pushl %edx
+ pushw %es
+ pushw %ds
+ movw %ss, %cx // Move %ss to %ds
+ movw %cx, %ds
+ lea 28(%esp), %eax // %eax points to start of u16 args
+ calll handle_pnp
+ movw %ax, 12(%esp) // Modify %eax to return %ax
+ popw %ds
+ popw %es
+ popl %edx
+ popl %ecx
+ popl %eax
+ popfl
+ popl %esp
+ lretw
+
+// APM entry points
+ DECLFUNC apm16protected_entry
apm16protected_entry:
pushfw // save flags
pushl %eax // dummy
lretw
.code32
- .global apm32protected_entry
+ DECLFUNC apm32protected_entry
apm32protected_entry:
pushfw
pushw %cs // Setup for long jump to 16bit mode
lretl
// 32bit elf entry point
- .global post32
+ EXPORTFUNC post32
post32:
cli
cld
lidtl (BUILD_BIOS_ADDR + pmode_IDT_info)
lgdtl (BUILD_BIOS_ADDR + rombios32_gdt_48)
+ movl $SEG32_MODE32_DS, %eax
+ movw %ax, %ds
+ movw %ax, %es
+ movw %ax, %fs
+ movw %ax, %gs
+ movw %ax, %ss
movl $BUILD_STACK_ADDR, %esp
- ljmpl $SEG32_MODE32_CS, $_code32__start
+ ljmpl $SEG32_MODE32_CS, $_start
.code16gcc
-// Shutdown a CPU. We want this in the 0xf000 section to ensure that
-// the code wont be overwritten with something else. (Should
-// something spurious wake up the CPU, we want to be sure that the hlt
-// insn will still be present and will shutdown the CPU.)
- .global permanent_halt
-permanent_halt:
- cli
-1: hlt
- jmp 1b
-
-
-/****************************************************************
- * GDT and IDT tables
- ****************************************************************/
-
-// Protected mode IDT descriptor
-//
-// I just make the limit 0, so the machine will shutdown
-// if an exception occurs during protected mode memory
-// transfers.
-//
-// Set base to f0000 to correspond to beginning of BIOS,
-// in case I actually define an IDT later
-// Set limit to 0
-pmode_IDT_info:
- .word 0x0000 // limit 15:00
- .long 0xf0000 // base 16:47
-
-// Real mode IDT descriptor
-//
-// Set to typical real-mode values.
-// base = 000000
-// limit = 03ff
-rmode_IDT_info:
- .word 0x03ff // limit 15:00
- .long 0 // base 16:47
-
-rombios32_gdt_48:
- .word 0x30
- .word rombios32_gdt
- .word 0x000f
-
- .balign 8
-rombios32_gdt:
- .word 0, 0, 0, 0
- .word 0, 0, 0, 0
- // 32 bit flat code segment (SEG32_MODE32_CS)
- .word 0xffff, 0, 0x9b00, 0x00cf
- // 32 bit flat data segment (SEG32_MODE32_DS)
- .word 0xffff, 0, 0x9300, 0x00cf
- // 16 bit code segment base=0xf0000 limit=0xffff (SEG32_MODE16_CS)
- .word 0xffff, 0, 0x9b0f, 0x0000
- // 16 bit data segment base=0x0 limit=0xffff (SEG32_MODE16_DS)
- .word 0xffff, 0, 0x9300, 0x0000
-
-// We need a copy of this string in the 0xf000 segment, but we are not
-// actually a PnP BIOS, so make sure it is *not* aligned, so OSes will
-// not see it if they scan.
- .global pnp_string
- .balign 2
- .byte 0
-pnp_string:
- .ascii "$PnP"
-
/****************************************************************
* Interrupt entry points
.macro IRQ_ENTRY num
.global entry_\num
entry_\num :
- cli // In case something far-calls instead of using "int"
- ENTRY handle_\num
- iretw
+ pushl $ handle_\num
+ jmp irqentry
.endm
// Define an entry point for an interrupt (can read/modify args).
.macro IRQ_ENTRY_ARG num
.global entry_\num
entry_\num :
- cli // In case something far-calls instead of using "int"
- ENTRY_ARG handle_\num
+ pushl $ handle_\num
+ jmp irqentryarg
+ .endm
+
+ // Macros that put each handler into its own section
+ .macro DECL_IRQ_ENTRY num
+ DECLFUNC entry_\num
+ IRQ_ENTRY \num
+ .endm
+ .macro DECL_IRQ_ENTRY_ARG num
+ DECLFUNC entry_\num
+ IRQ_ENTRY_ARG \num
+ .endm
+
+ // Main entry point for interrupts without args
+ DECLFUNC irqentry
+irqentry:
+ ENTRY_ST
iretw
+
+ // Main entry point for interrupts with args
+ DECLFUNC irqentryarg
+irqentryarg:
+ ENTRY_ARG_ST
+ iretw
+
+ DECL_IRQ_ENTRY_ARG 13
+ DECL_IRQ_ENTRY 76
+ DECL_IRQ_ENTRY 70
+ DECL_IRQ_ENTRY 74
+ DECL_IRQ_ENTRY 75
+ DECL_IRQ_ENTRY hwpic1
+ DECL_IRQ_ENTRY hwpic2
+
+ // int 18/19 are special - they reset stack and call into 32bit mode.
+ DECLFUNC entry_19
+entry_19:
+ ENTRY_INTO32 handle_19
+
+ DECLFUNC entry_18
+entry_18:
+ ENTRY_INTO32 handle_18
+
+
+/****************************************************************
+ * Fixed position entry points
+ ****************************************************************/
+
+ // Specify a location in the fixed part of bios area.
+ .macro ORG addr
+ .section .fixedaddr.\addr
.endm
- ORG 0xe2c3
- IRQ_ENTRY nmi
+ ORG 0xe05b
+entry_post_official:
+ jmp entry_post
- IRQ_ENTRY_ARG 13
- IRQ_ENTRY_ARG 12
- IRQ_ENTRY_ARG 11
- IRQ_ENTRY 76
- IRQ_ENTRY 1c
- IRQ_ENTRY 70
+ ORG 0xe2c3
+ IRQ_ENTRY 02
ORG 0xe3fe
+ .global entry_13_official
+entry_13_official:
jmp entry_13
- ORG 0xe401
- // XXX - Fixed Disk Parameter Table
+ // 0xe401 - OldFDPT in disk.c
ORG 0xe6f2
+ .global entry_19_official
+entry_19_official:
jmp entry_19
- ORG 0xe6f5
-.include "out/cbt.proc.16.s"
- .text
+ // 0xe6f5 - BIOS_CONFIG_TABLE in misc.c
- ORG 0xe729
- // XXX - Baud Rate Generator Table
+ // 0xe729 - BaudTable in serial.c
ORG 0xe739
IRQ_ENTRY_ARG 14
- IRQ_ENTRY 74
- IRQ_ENTRY 75
-
- // int 18/19 are special - they reset the stack and do not return.
- .global entry_19
-entry_19:
- RESET_STACK
- pushl $_code32_handle_19
- jmp transition32
-
- .global entry_18
-entry_18:
- RESET_STACK
- pushl $_code32_handle_18
- jmp transition32
-
- // IRQ trampolines
- .macro IRQ_TRAMPOLINE num
- .global irq_trampoline_0x\num
- irq_trampoline_0x\num :
- int $0x\num
- lretw
- .endm
-
- IRQ_TRAMPOLINE 02
- IRQ_TRAMPOLINE 10
- IRQ_TRAMPOLINE 13
- IRQ_TRAMPOLINE 15
- IRQ_TRAMPOLINE 16
- IRQ_TRAMPOLINE 18
- IRQ_TRAMPOLINE 19
- IRQ_TRAMPOLINE 1c
- IRQ_TRAMPOLINE 4a
-
ORG 0xe82e
IRQ_ENTRY_ARG 16
- .global entry_hwirq
-entry_hwirq:
- ENTRY handle_hwirq
-
ORG 0xe987
IRQ_ENTRY 09
ORG 0xef57
IRQ_ENTRY 0e
- ORG 0xefc7
-.include "out/floppy_dbt.proc.16.s"
- .text
+ // 0xefc7 - diskette_param_table in floppy.c
ORG 0xefd2
IRQ_ENTRY_ARG 17
ORG 0xf045
- // XXX int 10
+entry_10_0x0f:
+ // XXX - INT 10 Functions 0-Fh Entry Point
iretw
ORG 0xf065
IRQ_ENTRY_ARG 10
- ORG 0xf0a4
- // XXX int 1D
- iretw
-
- .global freespace2_start, freespace2_end
-freespace2_start:
+ // 0xf0a4 - VideoParams in misc.c
ORG 0xf841
-freespace2_end:
- jmp entry_12
+ IRQ_ENTRY_ARG 12
ORG 0xf84d
- jmp entry_11
+ IRQ_ENTRY_ARG 11
ORG 0xf859
IRQ_ENTRY_ARG 15
- ORG 0xfa6e
-.include "out/font.proc.16.s"
- .text
+ // 0xfa6e - vgafont8 in font.c
ORG 0xfe6e
IRQ_ENTRY_ARG 1a
ORG 0xfea5
IRQ_ENTRY 08
- ORG 0xfef3
- // XXX - Initial Interrupt Vector Offsets Loaded by POST
+ // 0xfef3 - InitVectors in misc.c
- ORG 0xff00
- // XXX - BIOS_COPYRIGHT_STRING
- .ascii "(c) 2002 MandrakeSoft S.A. Written by Kevin Lawton & the Bochs team."
+ // 0xff00 - BiosCopyright in misc.c
ORG 0xff53
- .global dummy_iret_handler
-dummy_iret_handler:
+ .global entry_iret_official
+entry_iret_official:
iretw
ORG 0xff54
IRQ_ENTRY_ARG 05
ORG 0xfff0 // Power-up Entry Point
- ljmpw $SEG_BIOS, $post16
+ .global reset_vector
+reset_vector:
+ ljmpw $SEG_BIOS, $entry_post_official
- ORG 0xfff5
- // BIOS build date
- .ascii "06/23/99"
+ // 0xfff5 - BiosDate in misc.c
- ORG 0xfffe
- .byte CONFIG_MODEL_ID
+ // 0xfffe - BiosModelId in misc.c
- .global bios_checksum
-bios_checksum:
- .byte 0x00
+ // 0xffff - BiosChecksum in misc.c
.end