sync with c; .text is implied
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3 changed files with 25 additions and 18 deletions
19
bootasm.S
19
bootasm.S
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@ -5,15 +5,16 @@
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# memory at physical address 0x7c00 and starts executing in real mode
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# with %cs=0 %ip=7c00.
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.set CSEG32, 0x8 # kernel code segment selector
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.set DSEG32, 0x10 # kernel data segment selector
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.set CR0_PE, 0x1 # protected mode enable flag
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#define SEG_KCODE 1 // kernel code
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#define SEG_KDATA 2 // kernel data+stack
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#define SEG_KCPU 3 // kernel per-cpu data
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#define CR0_PE 1 // protected mode enable bit
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.code16 # Assemble for 16-bit mode
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.globl start
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start:
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cli # Disable interrupts
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cld # String operations increment
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# Set up the important data segment registers (DS, ES, SS).
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xorw %ax,%ax # Segment number zero
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@ -53,17 +54,18 @@ seta20.2:
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# Jump to next instruction, but in 32-bit code segment.
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# Switches processor into 32-bit mode.
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ljmp $CSEG32, $start32
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ljmp $(SEG_KCODE<<3), $start32
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.code32 # Assemble for 32-bit mode
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start32:
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# Set up the protected-mode data segment registers
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movw $DSEG32, %ax # Our data segment selector
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movw $(SEG_KDATA<<3), %ax # Our data segment selector
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movw %ax, %ds # -> DS: Data Segment
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movw %ax, %es # -> ES: Extra Segment
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movw %ax, %ss # -> SS: Stack Segment
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movw $(SEG_KCPU<<3), %ax # Our per-cpu segment selector
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movw %ax, %fs # -> FS
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movw %ax, %gs # -> GS
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movw %ax, %ss # -> SS: Stack Segment
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# Set up the stack pointer and call into C.
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movl $start, %esp
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@ -85,7 +87,8 @@ gdt:
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SEG_NULLASM # null seg
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SEG_ASM(STA_X|STA_R, 0x0, 0xffffffff) # code seg
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SEG_ASM(STA_W, 0x0, 0xffffffff) # data seg
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SEG_ASM(STA_W, 0x100, 0xffffffff) # per-cpu data seg; 0x100 is okay for now
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gdtdesc:
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.word 0x17 # sizeof(gdt) - 1
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.word 0x1f # sizeof(gdt) - 1
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.long gdt # address gdt
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20
trapasm.S
20
trapasm.S
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@ -1,6 +1,6 @@
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.text
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.set SEG_KDATA_SEL, 0x10 # selector for SEG_KDATA
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#define SEG_KCODE 1 // kernel code
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#define SEG_KDATA 2 // kernel data+stack
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#define SEG_KCPU 3 // kernel per-cpu data
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# vectors.S sends all traps here.
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.globl alltraps
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@ -12,10 +12,16 @@ alltraps:
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pushl %gs
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pushal
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# Set up data segments.
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movl $SEG_KDATA_SEL, %eax
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movw %ax,%ds
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movw %ax,%es
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# Set up data and per-cpu segments.
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# Can find out KDATA from %ss.
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# Assume that KCPU is KDATA+1.
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movw $(SEG_KDATA<<3), %ax
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movw %ss, %ax
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movw %ax, %ds
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movw %ax, %es
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movw $(SEG_KCPU<<3), %ax
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movw %ax, %fs
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movw %ax, %gs
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# Call trap(tf), where tf=%esp
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pushl %esp
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@ -7,7 +7,6 @@
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print "# generated by vectors.pl - do not edit\n";
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print "# handlers\n";
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print ".text\n";
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print ".globl alltraps\n";
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for(my $i = 0; $i < 256; $i++){
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print ".globl vector$i\n";
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@ -29,7 +28,6 @@ for(my $i = 0; $i < 256; $i++){
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# sample output:
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# # handlers
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# .text
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# .globl alltraps
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# .globl vector0
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# vector0:
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