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sync with c; .text is implied

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rsc 2009-05-31 01:00:38 +00:00
parent ba6cd8a685
commit e97519a6d2
3 changed files with 25 additions and 18 deletions
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19
bootasm.S
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@ -5,15 +5,16 @@
# memory at physical address 0x7c00 and starts executing in real mode
# with %cs=0 %ip=7c00.
.set CSEG32, 0x8 # kernel code segment selector
.set DSEG32, 0x10 # kernel data segment selector
.set CR0_PE, 0x1 # protected mode enable flag
#define SEG_KCODE 1 // kernel code
#define SEG_KDATA 2 // kernel data+stack
#define SEG_KCPU 3 // kernel per-cpu data
#define CR0_PE 1 // protected mode enable bit
.code16 # Assemble for 16-bit mode
.globl start
start:
cli # Disable interrupts
cld # String operations increment
# Set up the important data segment registers (DS, ES, SS).
xorw %ax,%ax # Segment number zero
@ -53,17 +54,18 @@ seta20.2:
# Jump to next instruction, but in 32-bit code segment.
# Switches processor into 32-bit mode.
ljmp $CSEG32, $start32
ljmp $(SEG_KCODE<<3), $start32
.code32 # Assemble for 32-bit mode
start32:
# Set up the protected-mode data segment registers
movw $DSEG32, %ax # Our data segment selector
movw $(SEG_KDATA<<3), %ax # Our data segment selector
movw %ax, %ds # -> DS: Data Segment
movw %ax, %es # -> ES: Extra Segment
movw %ax, %ss # -> SS: Stack Segment
movw $(SEG_KCPU<<3), %ax # Our per-cpu segment selector
movw %ax, %fs # -> FS
movw %ax, %gs # -> GS
movw %ax, %ss # -> SS: Stack Segment
# Set up the stack pointer and call into C.
movl $start, %esp
@ -85,7 +87,8 @@ gdt:
SEG_NULLASM # null seg
SEG_ASM(STA_X|STA_R, 0x0, 0xffffffff) # code seg
SEG_ASM(STA_W, 0x0, 0xffffffff) # data seg
SEG_ASM(STA_W, 0x100, 0xffffffff) # per-cpu data seg; 0x100 is okay for now
gdtdesc:
.word 0x17 # sizeof(gdt) - 1
.word 0x1f # sizeof(gdt) - 1
.long gdt # address gdt

20
trapasm.S
View file

@ -1,6 +1,6 @@
.text
.set SEG_KDATA_SEL, 0x10 # selector for SEG_KDATA
#define SEG_KCODE 1 // kernel code
#define SEG_KDATA 2 // kernel data+stack
#define SEG_KCPU 3 // kernel per-cpu data
# vectors.S sends all traps here.
.globl alltraps
@ -12,10 +12,16 @@ alltraps:
pushl %gs
pushal
# Set up data segments.
movl $SEG_KDATA_SEL, %eax
movw %ax,%ds
movw %ax,%es
# Set up data and per-cpu segments.
# Can find out KDATA from %ss.
# Assume that KCPU is KDATA+1.
movw $(SEG_KDATA<<3), %ax
movw %ss, %ax
movw %ax, %ds
movw %ax, %es
movw $(SEG_KCPU<<3), %ax
movw %ax, %fs
movw %ax, %gs
# Call trap(tf), where tf=%esp
pushl %esp

2
vectors.pl
View file

@ -7,7 +7,6 @@
print "# generated by vectors.pl - do not edit\n";
print "# handlers\n";
print ".text\n";
print ".globl alltraps\n";
for(my $i = 0; $i < 256; $i++){
print ".globl vector$i\n";
@ -29,7 +28,6 @@ for(my $i = 0; $i < 256; $i++){
# sample output:
# # handlers
# .text
# .globl alltraps
# .globl vector0
# vector0: