#include "x16.h"
#include "mem.h"
#ifdef PXE
#define PDB 0x90000 /* temporary page tables (24KB) */
#else
#define PDB 0x08000
#endif PXE
#define NoScreenBlank 1
/*#define ResetDiscs 1*/
TEXT origin(SB), $0
/*
* This part of l.s is used only in the boot kernel.
* It assumes that we are in real address mode, i.e.,
* that we look like an 8086.
*
* Make sure the segments are reasonable.
* If we were started directly from the BIOS
* (i.e. no MS-DOS) then DS may not be
* right.
*/
MOVW CS, AX
MOVW AX, DS
#ifdef NoScreenBlank
/*
* Get the current video mode. If it isn't mode 3,
* set text mode 3.
* Well, no. Windows95 won't co-operate here so we have
* to explicitly set mode 3.
*/
XORL AX, AX
MOVB $0x0F, AH
INT $0x10 /* get current video mode in AL */
CMPB AL, $03
JEQ sayhello
#endif /* NoScreenBlank */
XORL AX, AX
MOVB $0x03, AL
INT $0x10 /* set video mode in AL */
sayhello:
LWI(hello(SB), rSI)
CALL16(biosputs(SB))
#ifdef ResetDiscs
XORL AX, AX /* reset disc system */
XORL DX, DX
MOVB $0x80, DL
INT $0x13
#endif /* ResetDiscs */
#ifdef DOTCOM
/*
* relocate everything to a half meg and jump there
* - looks weird because it is being assembled by a 32 bit
* assembler for a 16 bit world
*
* only b.com does this - not 9load
*/
MOVL $0,BX
INCL BX
SHLL $15,BX
MOVL BX,CX
MOVW BX,ES
MOVL $0,SI
MOVL SI,DI
CLD
REP
MOVSL
/*
* Jump to the copied image;
* fix up the DS for the new location.
*/
FARJUMP16(0x8000, _start8000(SB))
TEXT _start8000(SB), $0
MFSR(rCS, rAX) /* fix up DS, ES (0x8000) */
MTSR(rAX, rDS)
MTSR(rAX, rES)
/*
* If we are already in protected mode, have to get back
* to real mode before trying any privileged operations
* (like going into protected mode...).
* Try to reset with a restart vector.
*/
MFCR(rCR0, rAX) /* are we in protected mode? */
ANDI(0x0001, rAX)
JEQ _real
CLR(rBX)
MTSR(rBX, rES)
LWI(0x0467, rBX) /* reset entry point */
LWI(_start8000(SB), rAX) /* offset within segment */
BYTE $0x26
BYTE $0x89
BYTE $0x07 /* MOVW AX, ES:[BX] */
LBI(0x69, rBL)
MFSR(rCS, rAX) /* segment */
BYTE $0x26
BYTE $0x89
BYTE $0x07 /* MOVW AX, ES:[BX] */
CLR(rDX)
OUTPORTB(0x70, 0x8F)
OUTPORTB(0x71, 0x0A)
FARJUMP16(0xFFFF, 0x0000) /* reset */
#endif /* DOTCOM */
_real:
/*
* do things that need to be done in real mode.
* the results get written to CONFADDR (0x1200)
* in a series of <4-byte-magic-number><block-of-data>
* the data length is dependent on the magic number.
*
* this gets parsed by conf.c:/^readlsconf
*
* N.B. CALL16 kills rDI, so we can't call anything.
*/
LWI(0x0000, rAX)
MTSR(rAX, rES)
LWI(0x1200, rDI)
/*
* turn off interrupts
*/
CLI
/*
* detect APM1.2 bios support
*/
/* save DI */
SW(rDI, rock(SB))
/* disconnect anyone else */
LWI(0x5304, rAX)
LWI(0x0000, rBX)
INT $0x15
/* connect */
CLC
LWI(0x5303, rAX)
LWI(0x0000, rBX)
INT $0x15
CLI /* apm put interrupts back? */
JC noapm
OPSIZE; PUSHR(rSI)
OPSIZE; PUSHR(rBX)
PUSHR(rDI)
PUSHR(rDX)
PUSHR(rCX)
PUSHR(rAX)
/* put DI, ES back */
LW(rock(SB), rDI)
LWI(0x0000, rAX)
MTSR(rAX, rES)
/*
* write APM data. first four bytes are APM\0.
*/
LWI(0x5041, rAX)
STOSW
LWI(0x004d, rAX)
STOSW
LWI(8, rCX)
apmmove:
POPR(rAX)
STOSW
LOOP apmmove
noapm:
/*
* end of real mode hacks: write terminator, put ES back.
*/
LWI(0x0000, rAX)
STOSW
STOSW
MFSR(rCS, rAX) /* fix up ES (0x8000) */
MTSR(rAX, rES)
/*
* goto protected mode
*/
/* MOVL tgdtptr(SB),GDTR /**/
BYTE $0x0f
BYTE $0x01
BYTE $0x16
WORD $tgdtptr(SB)
LWI(1, rAX)
/* MOV AX,MSW */
BYTE $0x0F; BYTE $0x01; BYTE $0xF0
/*
* clear prefetch queue (weird code to avoid optimizations)
*/
/* JMP .+2 */
BYTE $0xEB
BYTE $0x00
/*
* set all segs
*/
/* MOVW $SELECTOR(1, SELGDT, 0),AX /**/
BYTE $0xc7
BYTE $0xc0
WORD $SELECTOR(1, SELGDT, 0)
MOVW AX,DS
MOVW AX,SS
MOVW AX,ES
MOVW AX,FS
MOVW AX,GS
/* JMPFAR SELECTOR(2, SELGDT, 0):$mode32bit(SB) /**/
BYTE $0x66
BYTE $0xEA
LONG $mode32bit-KZERO(SB)
WORD $SELECTOR(2, SELGDT, 0)
TEXT mode32bit(SB),$0
/*
* make a bottom level page table page that maps the first
* 16 meg of physical memory
*/
MOVL $PDB, DI /* clear 6 pages for the tables etc. */
XORL AX, AX
MOVL $(6*BY2PG), CX
SHRL $2, CX
CLD
REP; STOSL
MOVL $PDB, AX /* phys addr of temporary page table */
MOVL $(4*1024),CX /* pte's per page */
MOVL $((((4*1024)-1)<<PGSHIFT)|PTEVALID|PTEKERNEL|PTEWRITE),BX
setpte:
MOVL BX,-4(AX)(CX*4)
SUBL $(1<<PGSHIFT),BX
LOOP setpte
/*
* make a top level page table page that maps the first
* 16 meg of memory to 0 thru 16meg and to KZERO thru KZERO+16meg
*/
MOVL AX,BX
ADDL $(4*BY2PG),AX
ADDL $(PTEVALID|PTEKERNEL|PTEWRITE),BX
MOVL BX,0(AX)
MOVL BX,((((KZERO>>1)&0x7FFFFFFF)>>(2*PGSHIFT-1-4))+0)(AX)
ADDL $BY2PG,BX
MOVL BX,4(AX)
MOVL BX,((((KZERO>>1)&0x7FFFFFFF)>>(2*PGSHIFT-1-4))+4)(AX)
ADDL $BY2PG,BX
MOVL BX,8(AX)
MOVL BX,((((KZERO>>1)&0x7FFFFFFF)>>(2*PGSHIFT-1-4))+8)(AX)
ADDL $BY2PG,BX
MOVL BX,12(AX)
MOVL BX,((((KZERO>>1)&0x7FFFFFFF)>>(2*PGSHIFT-1-4))+12)(AX)
/*
* point processor to top level page & turn on paging
*
* this produces the apparently harmless "VMX|F(125):468 Dis 0x0:0x0"
* message in the VMware log.
*/
MOVL AX,CR3
MOVL CR0,AX
ORL $0X80000000,AX
MOVL AX,CR0
/*
* use a jump to an absolute location to get the PC into
* KZERO.
*/
LEAL tokzero(SB),AX
JMP* AX
/*
* When we load 9load from DOS, the bootstrap jumps
* to the instruction right after `JUMP', which gets
* us into kzero.
*
* The name prevents it from being optimized away.
*/
TEXT jumplabel(SB), $0
BYTE $'J'; BYTE $'U'; BYTE $'M'; BYTE $'P'
LEAL tokzero(SB),AX
JMP* AX
TEXT tokzero(SB),$0
/*
* Clear BSS
*/
LEAL edata(SB),SI
MOVL SI,DI
ADDL $4,DI
MOVL $0,AX
MOVL AX,(SI)
LEAL end(SB),CX
SUBL DI,CX
SHRL $2,CX
CLD
REP
MOVSL
/*
* stack and mach
*/
MOVL $mach0(SB),SP
MOVL SP,m(SB)
MOVL $0,0(SP)
ADDL $(MACHSIZE-4),SP /* start stack above machine struct */
CALL main(SB)
loop:
JMP loop
GLOBL mach0+0(SB), $MACHSIZE
GLOBL m(SB), $4
/*
* gdt to get us to 32-bit/segmented/unpaged mode
*/
TEXT tgdt(SB),$0
/* null descriptor */
LONG $0
LONG $0
/* data segment descriptor for 4 gigabytes (PL 0) */
LONG $(0xFFFF)
LONG $(SEGG|SEGB|(0xF<<16)|SEGP|SEGPL(0)|SEGDATA|SEGW)
/* exec segment descriptor for 4 gigabytes (PL 0) */
LONG $(0xFFFF)
LONG $(SEGG|SEGD|(0xF<<16)|SEGP|SEGPL(0)|SEGEXEC|SEGR)
/*
* pointer to initial gdt
*/
TEXT tgdtptr(SB),$0
WORD $(3*8)
LONG $tgdt-KZERO(SB)
/*
* Output a string to the display.
* String argument is in rSI.
*/
TEXT biosputs(SB), $0
PUSHA
CLR(rBX)
_BIOSputs:
LODSB
ORB(rAL, rAL)
JEQ _BIOSputsret
LBI(0x0E, rAH)
BIOSCALL(0x10)
JMP _BIOSputs
_BIOSputsret:
POPA
RET
/*
* input a byte
*/
TEXT inb(SB),$0
MOVL p+0(FP),DX
XORL AX,AX
INB
RET
/*
* input a short from a port
*/
TEXT ins(SB), $0
MOVL p+0(FP), DX
XORL AX, AX
OPSIZE; INL
RET
/*
* input a long from a port
*/
TEXT inl(SB), $0
MOVL p+0(FP), DX
XORL AX, AX
INL
RET
/*
* output a byte
*/
TEXT outb(SB),$0
MOVL p+0(FP),DX
MOVL b+4(FP),AX
OUTB
RET
/*
* output a short to a port
*/
TEXT outs(SB), $0
MOVL p+0(FP), DX
MOVL s+4(FP), AX
OPSIZE; OUTL
RET
/*
* output a long to a port
*/
TEXT outl(SB), $0
MOVL p+0(FP), DX
MOVL s+4(FP), AX
OUTL
RET
/*
* input a string of bytes from a port
*/
TEXT insb(SB),$0
MOVL p+0(FP),DX
MOVL a+4(FP),DI
MOVL c+8(FP),CX
CLD; REP; INSB
RET
/*
* input a string of shorts from a port
*/
TEXT inss(SB),$0
MOVL p+0(FP),DX
MOVL a+4(FP),DI
MOVL c+8(FP),CX
CLD
REP; OPSIZE; INSL
RET
/*
* output a string of bytes to a port
*/
TEXT outsb(SB),$0
MOVL p+0(FP),DX
MOVL a+4(FP),SI
MOVL c+8(FP),CX
CLD; REP; OUTSB
RET
/*
* output a string of shorts to a port
*/
TEXT outss(SB),$0
MOVL p+0(FP),DX
MOVL a+4(FP),SI
MOVL c+8(FP),CX
CLD
REP; OPSIZE; OUTSL
RET
/*
* input a string of longs from a port
*/
TEXT insl(SB),$0
MOVL p+0(FP),DX
MOVL a+4(FP),DI
MOVL c+8(FP),CX
CLD; REP; INSL
RET
/*
* output a string of longs to a port
*/
TEXT outsl(SB),$0
MOVL p+0(FP),DX
MOVL a+4(FP),SI
MOVL c+8(FP),CX
CLD; REP; OUTSL
RET
/*
* routines to load/read various system registers
*/
GLOBL idtptr(SB),$6
TEXT putidt(SB),$0 /* interrupt descriptor table */
MOVL t+0(FP),AX
MOVL AX,idtptr+2(SB)
MOVL l+4(FP),AX
MOVW AX,idtptr(SB)
MOVL idtptr(SB),IDTR
RET
TEXT putcr3(SB),$0 /* top level page table pointer */
MOVL t+0(FP),AX
MOVL AX,CR3
RET
TEXT getcr0(SB),$0 /* coprocessor bits */
MOVL CR0,AX
RET
TEXT getcr2(SB),$0 /* fault address */
MOVL CR2,AX
RET
TEXT getcr3(SB),$0 /* page directory base */
MOVL CR3,AX
RET
TEXT getcr4(SB), $0 /* CR4 - extensions */
MOVL CR4, AX
RET
/*
* special traps
*/
TEXT intr0(SB),$0
PUSHL $0
PUSHL $0
JMP intrcommon
TEXT intr1(SB),$0
PUSHL $0
PUSHL $1
JMP intrcommon
TEXT intr2(SB),$0
PUSHL $0
PUSHL $2
JMP intrcommon
TEXT intr3(SB),$0
PUSHL $0
PUSHL $3
JMP intrcommon
TEXT intr4(SB),$0
PUSHL $0
PUSHL $4
JMP intrcommon
TEXT intr5(SB),$0
PUSHL $0
PUSHL $5
JMP intrcommon
TEXT intr6(SB),$0
PUSHL $0
PUSHL $6
JMP intrcommon
TEXT intr7(SB),$0
PUSHL $0
PUSHL $7
JMP intrcommon
TEXT intr8(SB),$0
PUSHL $8
JMP intrcommon
TEXT intr9(SB),$0
PUSHL $0
PUSHL $9
JMP intrcommon
TEXT intr10(SB),$0
PUSHL $10
JMP intrcommon
TEXT intr11(SB),$0
PUSHL $11
JMP intrcommon
TEXT intr12(SB),$0
PUSHL $12
JMP intrcommon
TEXT intr13(SB),$0
PUSHL $13
JMP intrcommon
TEXT intr14(SB),$0
PUSHL $14
JMP intrcommon
TEXT intr15(SB),$0
PUSHL $0
PUSHL $15
JMP intrcommon
TEXT intr16(SB),$0
PUSHL $0
PUSHL $16
JMP intrcommon
TEXT intr24(SB),$0
PUSHL $0
PUSHL $24
JMP intrcommon
TEXT intr25(SB),$0
PUSHL $0
PUSHL $25
JMP intrcommon
TEXT intr26(SB),$0
PUSHL $0
PUSHL $26
JMP intrcommon
TEXT intr27(SB),$0
PUSHL $0
PUSHL $27
JMP intrcommon
TEXT intr28(SB),$0
PUSHL $0
PUSHL $28
JMP intrcommon
TEXT intr29(SB),$0
PUSHL $0
PUSHL $29
JMP intrcommon
TEXT intr30(SB),$0
PUSHL $0
PUSHL $30
JMP intrcommon
TEXT intr31(SB),$0
PUSHL $0
PUSHL $31
JMP intrcommon
TEXT intr32(SB),$0
PUSHL $0
PUSHL $32
JMP intrcommon
TEXT intr33(SB),$0
PUSHL $0
PUSHL $33
JMP intrcommon
TEXT intr34(SB),$0
PUSHL $0
PUSHL $34
JMP intrcommon
TEXT intr35(SB),$0
PUSHL $0
PUSHL $35
JMP intrcommon
TEXT intr36(SB),$0
PUSHL $0
PUSHL $36
JMP intrcommon
TEXT intr37(SB),$0
PUSHL $0
PUSHL $37
JMP intrcommon
TEXT intr38(SB),$0
PUSHL $0
PUSHL $38
JMP intrcommon
TEXT intr39(SB),$0
PUSHL $0
PUSHL $39
JMP intrcommon
TEXT intr64(SB),$0
PUSHL $0
PUSHL $64
JMP intrcommon
TEXT intrbad(SB),$0
PUSHL $0
PUSHL $0x1ff
JMP intrcommon
intrcommon:
PUSHL DS
PUSHL ES
PUSHL FS
PUSHL GS
PUSHAL
MOVL $(KDSEL),AX
MOVW AX,DS
MOVW AX,ES
LEAL 0(SP),AX
PUSHL AX
CALL trap(SB)
POPL AX
POPAL
POPL GS
POPL FS
POPL ES
POPL DS
ADDL $8,SP /* error code and trap type */
IRETL
/*
* interrupt level is interrupts on or off
*/
TEXT spllo(SB),$0
PUSHFL
POPL AX
STI
RET
TEXT splhi(SB),$0
PUSHFL
POPL AX
CLI
RET
TEXT splx(SB),$0
MOVL s+0(FP),AX
PUSHL AX
POPFL
RET
/*
* do nothing whatsoever till interrupt happens
*/
TEXT idle(SB),$0
HLT
RET
/*
* Try to determine the CPU type which requires fiddling with EFLAGS.
* If the Id bit can be toggled then the CPUID instruciton can be used
* to determine CPU identity and features. First have to check if it's
* a 386 (Ac bit can't be set). If it's not a 386 and the Id bit can't be
* toggled then it's an older 486 of some kind.
*
* cpuid(id[], &ax, &dx);
*/
#define CPUID BYTE $0x0F; BYTE $0xA2 /* CPUID, argument in AX */
TEXT cpuid(SB), $0
MOVL $0x240000, AX
PUSHL AX
POPFL /* set Id|Ac */
PUSHFL
POPL BX /* retrieve value */
MOVL $0, AX
PUSHL AX
POPFL /* clear Id|Ac, EFLAGS initialised */
PUSHFL
POPL AX /* retrieve value */
XORL BX, AX
TESTL $0x040000, AX /* Ac */
JZ _cpu386 /* can't set this bit on 386 */
TESTL $0x200000, AX /* Id */
JZ _cpu486 /* can't toggle this bit on some 486 */
MOVL $0, AX
CPUID
MOVL id+0(FP), BP
MOVL BX, 0(BP) /* "Genu" "Auth" "Cyri" */
MOVL DX, 4(BP) /* "ineI" "enti" "xIns" */
MOVL CX, 8(BP) /* "ntel" "cAMD" "tead" */
MOVL $1, AX
CPUID
JMP _cpuid
_cpu486:
MOVL $0x400, AX
MOVL $0, DX
JMP _cpuid
_cpu386:
MOVL $0x300, AX
MOVL $0, DX
_cpuid:
MOVL ax+4(FP), BP
MOVL AX, 0(BP)
MOVL dx+8(FP), BP
MOVL DX, 0(BP)
RET
/*
* basic timing loop to determine CPU frequency
*/
TEXT aamloop(SB),$0
MOVL c+0(FP),CX
aaml1:
AAM
LOOP aaml1
RET
TEXT hello(SB), $0
BYTE $'P'; BYTE $'l'; BYTE $'a'; BYTE $'n';
BYTE $' '; BYTE $'9'; BYTE $' '; BYTE $'f';
BYTE $'r'; BYTE $'o'; BYTE $'m'; BYTE $' ';
BYTE $'B'; BYTE $'e'; BYTE $'l'; BYTE $'l';
BYTE $' '; BYTE $'L'; BYTE $'a'; BYTE $'b';
BYTE $'s';
BYTE $'\r';
BYTE $'\n';
BYTE $'\z';
TEXT rock(SB), $0
BYTE $0; BYTE $0; BYTE $0; BYTE $0;
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