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// Inferno utils/8a/l.s
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// http://code.google.com/p/inferno-os/source/browse/utils/8a/l.s
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// Copyright © 1994-1999 Lucent Technologies Inc. All rights reserved.
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// Portions Copyright © 1995-1997 C H Forsyth (forsyth@terzarima.net)
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// Portions Copyright © 1997-1999 Vita Nuova Limited
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// Portions Copyright © 2000-2007 Vita Nuova Holdings Limited (www.vitanuova.com)
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// Portions Copyright © 2004,2006 Bruce Ellis
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// Portions Copyright © 2005-2007 C H Forsyth (forsyth@terzarima.net)
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// Revisions Copyright © 2000-2007 Lucent Technologies Inc. and others
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// Portions Copyright © 2009 The Go Authors. All rights reserved.
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// Permission is hereby granted, free of charge, to any person obtaining a copy
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// of this software and associated documentation files (the "Software"), to deal
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// in the Software without restriction, including without limitation the rights
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// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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// copies of the Software, and to permit persons to whom the Software is
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// furnished to do so, subject to the following conditions:
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// The above copyright notice and this permission notice shall be included in
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// all copies or substantial portions of the Software.
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// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
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* Memory and machine-specific definitions. Used in C and assembler.
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#define BI2BY 8 /* bits per byte */
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#define BI2WD 32 /* bits per word */
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#define BY2WD 4 /* bytes per word */
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#define BY2PG 4096 /* bytes per page */
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#define WD2PG (BY2PG/BY2WD) /* words per page */
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#define PGSHIFT 12 /* log(BY2PG) */
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#define PGROUND(s) (((s)+(BY2PG-1))&~(BY2PG-1))
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#define MAXMACH 1 /* max # cpus system can run */
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#define HZ (20) /* clock frequency */
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#define MS2HZ (1000/HZ) /* millisec per clock tick */
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#define TK2SEC(t) ((t)/HZ) /* ticks to seconds */
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#define TK2MS(t) ((((ulong)(t))*1000)/HZ) /* ticks to milliseconds */
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#define MS2TK(t) ((((ulong)(t))*HZ)/1000) /* milliseconds to ticks */
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* Fundamental addresses
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* Kernel is at 2GB-4GB
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* To avoid an extra page map, both the user stack (USTKTOP) and
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* the temporary user stack (TSTKTOP) should be in the the same
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#define UZERO 0 /* base of user address space */
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#define UTZERO (UZERO+BY2PG) /* first address in user text */
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#define KZERO 0x80000000 /* base of kernel address space */
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#define KTZERO KZERO /* first address in kernel text */
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#define USERADDR 0xC0000000 /* struct User */
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#define UREGADDR (USERADDR+BY2PG-4*19)
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#define TSTKTOP USERADDR /* end of new stack in sysexec */
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#define USTKTOP (TSTKTOP-TSTKSIZ*BY2PG) /* byte just beyond user stack */
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#define USTKSIZE (16*1024*1024 - TSTKSIZ*BY2PG) /* size of user stack */
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#define ROMBIOS (KZERO|0xF0000)
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#define isphys(x) (((ulong)x)&KZERO)
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* known 80386 segments (in GDT) and their selectors
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#define NULLSEG 0 /* null segment */
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#define KDSEG 1 /* kernel data/stack */
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#define KESEG 2 /* kernel executable */
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#define UDSEG 3 /* user data/stack */
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#define UESEG 4 /* user executable */
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#define TSSSEG 5 /* task segment */
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#define SELGDT (0<<3) /* selector is in gdt */
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#define SELLDT (1<<3) /* selector is in ldt */
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#define SELECTOR(i, t, p) (((i)<<3) | (t) | (p))
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#define NULLSEL SELECTOR(NULLSEG, SELGDT, 0)
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#define KESEL SELECTOR(KESEG, SELGDT, 0)
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#define KDSEL SELECTOR(KDSEG, SELGDT, 0)
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#define UESEL SELECTOR(UESEG, SELGDT, 3)
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#define UDSEL SELECTOR(UDSEG, SELGDT, 3)
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#define TSSSEL SELECTOR(TSSSEG, SELGDT, 0)
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* fields in segment descriptors
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#define SEGDATA (0x10<<8) /* data/stack segment */
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#define SEGEXEC (0x18<<8) /* executable segment */
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#define SEGTSS (0x9<<8) /* TSS segment */
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#define SEGCG (0x0C<<8) /* call gate */
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#define SEGIG (0x0E<<8) /* interrupt gate */
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#define SEGTG (0x0F<<8) /* task gate */
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#define SEGTYPE (0x1F<<8)
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#define SEGP (1<<15) /* segment present */
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#define SEGPL(x) ((x)<<13) /* priority level */
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#define SEGB (1<<22) /* granularity 1==4k (for expand-down) */
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#define SEGG (1<<23) /* granularity 1==4k (for other) */
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#define SEGE (1<<10) /* expand down */
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#define SEGW (1<<9) /* writable (for data/stack) */
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#define SEGR (1<<9) /* readable (for code) */
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#define SEGD (1<<22) /* default 1==32bit (for code) */
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#define PTEMAPMEM (1024*1024) /* ??? */
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#define SEGMAPSIZE 16 /* ??? */
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#define PTEPERTAB (PTEMAPMEM/BY2PG) /* ??? */
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#define PPN(x) ((x)&~(BY2PG-1))
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#define PTEVALID (1<<0)
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#define PTEUNCACHED 0 /* everything is uncached */
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#define PTEWRITE (1<<1)
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#define PTERONLY (0<<1)
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#define PTEKERNEL (0<<2)
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#define PTEUSER (1<<2)
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* flag register bits that we care about
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#define OP16 BYTE $0x66
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* about to walk all over ms/dos - turn off interrupts
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* This part of l.s is used only in the boot kernel.
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* It assumes that we are in real address mode, i.e.,
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* that we look like an 8086.
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* relocate everything to a half meg and jump there
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* - looks wierd because it is being assembled by a 32 bit
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* assembler for a 16 bit world
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/* JMPFAR 0X8000:$lowcore(SB) /**/
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* now that we're in low core, update the DS
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* goto protected mode
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/* MOVL tgdtptr(SB),GDTR /**/
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* clear prefetch queue (wierd code to avoid optimizations)
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/* MOVW $SELECTOR(1, SELGDT, 0),AX /**/
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WORD $SELECTOR(1, SELGDT, 0)
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/* JMPFAR SELECTOR(2, SELGDT, 0):$mode32bit(SB) /**/
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LONG $mode32bit-KZERO(SB)
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WORD $SELECTOR(2, SELGDT, 0)
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TEXT mode32bit(SB),$0
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LEAL edata-KZERO(SB),SI
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LEAL end-KZERO(SB),CX
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* make a bottom level page table page that maps the first
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* 16 meg of physical memory
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LEAL tpt-KZERO(SB),AX /* get phys addr of temporary page table */
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ADDL $(BY2PG-1),AX /* must be page aligned */
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ANDL $(~(BY2PG-1)),AX /* ... */
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MOVL $(4*1024),CX /* pte's per page */
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MOVL $((((4*1024)-1)<<PGSHIFT)|PTEVALID|PTEKERNEL|PTEWRITE),BX
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SUBL $(1<<PGSHIFT),BX
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* make a top level page table page that maps the first
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* 16 meg of memory to 0 thru 16meg and to KZERO thru KZERO+16meg
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ADDL $(PTEVALID|PTEKERNEL|PTEWRITE),BX
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MOVL BX,((((KZERO>>1)&0x7FFFFFFF)>>(2*PGSHIFT-1-4))+0)(AX)
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MOVL BX,((((KZERO>>1)&0x7FFFFFFF)>>(2*PGSHIFT-1-4))+4)(AX)
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MOVL BX,((((KZERO>>1)&0x7FFFFFFF)>>(2*PGSHIFT-1-4))+8)(AX)
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MOVL BX,((((KZERO>>1)&0x7FFFFFFF)>>(2*PGSHIFT-1-4))+12)(AX)
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* point processor to top level page & turn on paging
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ANDL $~(0x8|0x2),AX /* TS=0, MP=0 */
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* use a jump to an absolute location to get the PC into
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ADDL $(MACHSIZE-4),SP /* start stack under machine struct */
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GLOBL mach0+0(SB), $MACHSIZE
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GLOBL tpt(SB), $(BY2PG*6)
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* gdt to get us to 32-bit/segmented/unpaged mode
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/* null descriptor */
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/* data segment descriptor for 4 gigabytes (PL 0) */
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LONG $(SEGG|SEGB|(0xF<<16)|SEGP|SEGPL(0)|SEGDATA|SEGW)
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/* exec segment descriptor for 4 gigabytes (PL 0) */
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LONG $(SEGG|SEGD|(0xF<<16)|SEGP|SEGPL(0)|SEGEXEC|SEGR)
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* pointer to initial gdt
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* input a string of shorts from a port
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* output a string of shorts to a port
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CLD; REP; OP16; OUTSL
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* routines to load/read various system registers
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TEXT putidt(SB),$0 /* interrupt descriptor table */
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TEXT putgdt(SB),$0 /* global descriptor table */
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TEXT putcr3(SB),$0 /* top level page table pointer */
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TEXT puttr(SB),$0 /* task register */
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TEXT getcr0(SB),$0 /* coprocessor bits */
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TEXT getcr2(SB),$0 /* fault address */
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ORL $0x4,AX /* EM=1 */;\
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ANDL $~0x4,AX /* EM=0 */;\
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TEXT fpoff(SB),$0 /* turn off floating point */
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TEXT fpinit(SB),$0 /* turn on & init the floating point */
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FLDCW 0(SP) /* ignore underflow/precision, signal others */
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TEXT fpsave(SB),$0 /* save floating point state and turn off */
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TEXT fprestore(SB),$0 /* turn on floating point and restore regs */
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TEXT fpstatus(SB),$0 /* get floating point status */
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ADDL $8,SP /* error code and trap type */
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ADDL $8,SP /* error code and trap type */
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* interrupt level is interrupts on or off
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* do nothing whatsoever till interrupt happens
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* label consists of a stack pointer and a PC
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TEXT gotolabel(SB),$0
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MOVL 0(AX),SP /* restore sp */
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MOVL 4(AX),AX /* put return pc on the stack */
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MOVL $1,AX /* return 1 */
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MOVL SP,0(AX) /* store sp */
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MOVL 0(SP),BX /* store return pc */
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MOVL $0,AX /* return 0 */
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* Used to get to the first process.
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* Set up an interrupt return frame and IRET to user level.
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PUSHL $(UDSEL) /* old ss */
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PUSHL $(USTKTOP) /* old sp */
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PUSHFL /* old flags */
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PUSHL $(UESEL) /* old cs */
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PUSHL $(UTZERO+32) /* old pc */
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* set configuration register
added
removed
src/cmd/8a/l.s
