* Memory and machine-specific definitions. Used in C and assembler.

/*
* Memory and machine-specific definitions. Used in C and assembler.
*/

/*
* Sizes
*/
#define BI2BY 8 /* bits per byte */
#define BI2WD 32 /* bits per word */
#define BY2WD 4 /* bytes per word */
#define BY2PG 4096 /* bytes per page */
#define WD2PG (BY2PG/BY2WD) /* words per page */
#define PGSHIFT 12 /* log(BY2PG) */
#define PGROUND(s) (((s)+(BY2PG-1))&~(BY2PG-1))

#define MAXMACH 1 /* max # cpus system can run */

/*
* Time
*/
#define HZ (20) /* clock frequency */
#define MS2HZ (1000/HZ) /* millisec per clock tick */
#define TK2SEC(t) ((t)/HZ) /* ticks to seconds */
#define TK2MS(t) ((((ulong)(t))*1000)/HZ) /* ticks to milliseconds */
#define MS2TK(t) ((((ulong)(t))*HZ)/1000) /* milliseconds to ticks */

/*
* Fundamental addresses
*/

/*
* Address spaces
*
* User is at 0-2GB
* Kernel is at 2GB-4GB
*
* To avoid an extra page map, both the user stack (USTKTOP) and
* the temporary user stack (TSTKTOP) should be in the the same
* 4 meg.
*/
#define UZERO 0 /* base of user address space */
#define UTZERO (UZERO+BY2PG) /* first address in user text */
#define KZERO 0x80000000 /* base of kernel address space */
#define KTZERO KZERO /* first address in kernel text */
#define USERADDR 0xC0000000 /* struct User */
#define UREGADDR (USERADDR+BY2PG-4*19)
#define TSTKTOP USERADDR /* end of new stack in sysexec */
#define TSTKSIZ 10
#define USTKTOP (TSTKTOP-TSTKSIZ*BY2PG) /* byte just beyond user stack */
#define USTKSIZE (16*1024*1024 - TSTKSIZ*BY2PG) /* size of user stack */
#define ROMBIOS (KZERO|0xF0000)

#define MACHSIZE 4096

#define isphys(x) (((ulong)x)&KZERO)

/*
* known 80386 segments (in GDT) and their selectors
*/
#define NULLSEG 0 /* null segment */
#define KDSEG 1 /* kernel data/stack */
#define KESEG 2 /* kernel executable */
#define UDSEG 3 /* user data/stack */
#define UESEG 4 /* user executable */
#define TSSSEG 5 /* task segment */

#define SELGDT (0<<3) /* selector is in gdt */
#define SELLDT (1<<3) /* selector is in ldt */

#define SELECTOR(i, t, p) (((i)<<3) | (t) | (p))

#define NULLSEL SELECTOR(NULLSEG, SELGDT, 0)
#define KESEL SELECTOR(KESEG, SELGDT, 0)
#define KDSEL SELECTOR(KDSEG, SELGDT, 0)
#define UESEL SELECTOR(UESEG, SELGDT, 3)
#define UDSEL SELECTOR(UDSEG, SELGDT, 3)
#define TSSSEL SELECTOR(TSSSEG, SELGDT, 0)

/*
* fields in segment descriptors
*/
#define SEGDATA (0x10<<8) /* data/stack segment */
#define SEGEXEC (0x18<<8) /* executable segment */
#define SEGTSS (0x9<<8) /* TSS segment */
#define SEGCG (0x0C<<8) /* call gate */
#define SEGIG (0x0E<<8) /* interrupt gate */
#define SEGTG (0x0F<<8) /* task gate */
#define SEGTYPE (0x1F<<8)

#define SEGP (1<<15) /* segment present */
#define SEGPL(x) ((x)<<13) /* priority level */
#define SEGB (1<<22) /* granularity 1==4k (for expand-down) */
#define SEGG (1<<23) /* granularity 1==4k (for other) */
#define SEGE (1<<10) /* expand down */
#define SEGW (1<<9) /* writable (for data/stack) */
#define SEGR (1<<9) /* readable (for code) */
#define SEGD (1<<22) /* default 1==32bit (for code) */

/*
* virtual MMU
*/
#define PTEMAPMEM (1024*1024) /* ??? */
#define SEGMAPSIZE 16 /* ??? */
#define PTEPERTAB (PTEMAPMEM/BY2PG) /* ??? */
#define PPN(x) ((x)&~(BY2PG-1))

/*
* physical MMU
*/
#define PTEVALID (1<<0)
#define PTEUNCACHED 0 /* everything is uncached */
#define PTEWRITE (1<<1)
#define PTERONLY (0<<1)
#define PTEKERNEL (0<<2)
#define PTEUSER (1<<2)

/*
* flag register bits that we care about
*/
#define IFLAG 0x200

#define OP16 BYTE $0x66

/*
* about to walk all over ms/dos - turn off interrupts
*/
TEXT origin(SB),$0

CLI

#ifdef BOOT
/*
* 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.
*/
/*
* relocate everything to a half meg and jump there
* - looks wierd because it is being assembled by a 32 bit
* assembler for a 16 bit world
*/
MOVL $0,BX
INCL BX
SHLL $15,BX
MOVL BX,CX
MOVW BX,ES
MOVL $0,SI
MOVL SI,DI
CLD; REP; MOVSL
/* JMPFAR 0X8000:$lowcore(SB) /**/
BYTE $0xEA
WORD $lowcore(SB)
WORD $0X8000

TEXT lowcore(SB),$0

/*
* now that we're in low core, update the DS
*/

MOVW BX,DS

/*
* goto protected mode
*/
/* MOVL tgdtptr(SB),GDTR /**/
BYTE $0x0f
BYTE $0x01
BYTE $0x16
WORD $tgdtptr(SB)
MOVL CR0,AX
ORL $1,AX
MOVL AX,CR0

/*
* clear prefetch queue (wierd code to avoid optimizations)
*/
CLC
JCC flush
MOVL AX,AX
flush:

/*
* 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

#endif BOOT

/*
* Clear BSS
*/
LEAL edata-KZERO(SB),SI
MOVL SI,DI
ADDL $4,DI
MOVL $0,AX
MOVL AX,(SI)
LEAL end-KZERO(SB),CX
SUBL DI,CX
SHRL $2,CX
CLD; REP; MOVSL

/*
* make a bottom level page table page that maps the first
* 16 meg of physical memory
*/
LEAL tpt-KZERO(SB),AX /* get phys addr of temporary page table */
ADDL $(BY2PG-1),AX /* must be page alligned */
ANDL $(~(BY2PG-1)),AX /* ... */
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
*/
MOVL AX,CR3
MOVL CR0,AX
ORL $0X80000000,AX
ANDL $~(0x8|0x2),AX /* TS=0, MP=0 */
MOVL AX,CR0

/*
* use a jump to an absolute location to get the PC into
* KZERO.
*/
LEAL tokzero(SB),AX
JMP* AX

TEXT tokzero(SB),$0

/*
* stack and mach
*/
MOVL $mach0(SB),SP
MOVL SP,m(SB)
MOVL $0,0(SP)
ADDL $(MACHSIZE-4),SP /* start stack under machine struct */
MOVL $0, u(SB)

/*
* clear flags
*/
MOVL $0,AX
PUSHL AX
POPFL

CALL main(SB)

loop:
JMP loop

GLOBL mach0+0(SB), $MACHSIZE
GLOBL u(SB), $4
GLOBL m(SB), $4
GLOBL tpt(SB), $(BY2PG*6)

/*
* 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)

/*
* input a byte
*/
TEXT inb(SB),$0

MOVL p+0(FP),DX
XORL AX,AX
INB
RET

/*
* output a byte
*/
TEXT outb(SB),$0

MOVL p+0(FP),DX
MOVL b+4(FP),AX
OUTB
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; OP16; INSL
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; OP16; OUTSL
RET

/*
* test and set
*/
TEXT tas(SB),$0
MOVL $0xdeadead,AX
MOVL l+0(FP),BX
XCHGL AX,(BX)
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

GLOBL gdtptr(SB),$6
TEXT putgdt(SB),$0 /* global descriptor table */
MOVL t+0(FP),AX
MOVL AX,gdtptr+2(SB)
MOVL l+4(FP),AX
MOVW AX,gdtptr(SB)
MOVL gdtptr(SB),GDTR
RET

TEXT putcr3(SB),$0 /* top level page table pointer */
MOVL t+0(FP),AX
MOVL AX,CR3
RET

TEXT puttr(SB),$0 /* task register */
MOVL t+0(FP),AX
MOVW AX,TASK
RET

TEXT getcr0(SB),$0 /* coprocessor bits */
MOVL CR0,AX
RET

TEXT getcr2(SB),$0 /* fault address */
MOVL CR2,AX
RET

#define FPOFF\
WAIT;\
MOVL CR0,AX;\
ORL $0x4,AX /* EM=1 */;\
MOVL AX,CR0

#define FPON\
MOVL CR0,AX;\
ANDL $~0x4,AX /* EM=0 */;\
MOVL AX,CR0

TEXT fpoff(SB),$0 /* turn off floating point */
FPOFF
RET

TEXT fpinit(SB),$0 /* turn on & init the floating point */
FPON
FINIT
WAIT
PUSHW $0x0330
FLDCW 0(SP) /* ignore underflow/precision, signal others */
POPW AX
WAIT
RET

TEXT fpsave(SB),$0 /* save floating point state and turn off */
MOVL p+0(FP),AX
WAIT
FSAVE 0(AX)
FPOFF
RET

TEXT fprestore(SB),$0 /* turn on floating point and restore regs */
FPON
MOVL p+0(FP),AX
FRSTOR 0(AX)
WAIT
RET

TEXT fpstatus(SB),$0 /* get floating point status */
FSTSW 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 intrscommon
TEXT intr9(SB),$0
PUSHL $0
PUSHL $9
JMP intrcommon
TEXT intr10(SB),$0
PUSHL $10
JMP intrscommon
TEXT intr11(SB),$0
PUSHL $11
JMP intrscommon
TEXT intr12(SB),$0
PUSHL $12
JMP intrscommon
TEXT intr13(SB),$0
PUSHL $13
JMP intrscommon
TEXT intr14(SB),$0
PUSHL $14
JMP intrscommon
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 $16
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

intrscommon:
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

/*
* label consists of a stack pointer and a PC
*/
TEXT gotolabel(SB),$0
MOVL l+0(FP),AX
MOVL 0(AX),SP /* restore sp */
MOVL 4(AX),AX /* put return pc on the stack */
MOVL AX,0(SP)
MOVL $1,AX /* return 1 */
RET

TEXT setlabel(SB),$0
MOVL l+0(FP),AX
MOVL SP,0(AX) /* store sp */
MOVL 0(SP),BX /* store return pc */
MOVL BX,4(AX)
MOVL $0,AX /* return 0 */
RET

/*
* Used to get to the first process.
* Set up an interrupt return frame and IRET to user level.
*/
TEXT touser(SB),$0
PUSHL $(UDSEL) /* old ss */
PUSHL $(USTKTOP) /* old sp */
PUSHFL /* old flags */
PUSHL $(UESEL) /* old cs */
PUSHL $(UTZERO+32) /* old pc */
MOVL $(UDSEL),AX
MOVW AX,DS
MOVW AX,ES
MOVW AX,GS
MOVW AX,FS
IRETL

/*
* set configuration register
*/
TEXT config(SB),$0
MOVL l+0(FP),AX
MOVL $0x3F3,DX
OUTB
OUTB
RET