/* $XConsortium: vgaBank.s,v 1.3 94/10/13 13:04:50 kaleb Exp $ */ /* $XFree86: xc/programs/Xserver/hw/xfree86/vga256/vga/vgaBank.s,v 3.3 1995/01/28 17:10:02 dawes Exp $ */ /* * Copyright 1990,91 by Thomas Roell, Dinkelscherben, Germany. * * Permission to use, copy, modify, distribute, and sell this software and its * documentation for any purpose is hereby granted without fee, provided that * the above copyright notice appear in all copies and that both that * copyright notice and this permission notice appear in supporting * documentation, and that the name of Thomas Roell not be used in * advertising or publicity pertaining to distribution of the software without * specific, written prior permission. Thomas Roell makes no representations * about the suitability of this software for any purpose. It is provided * "as is" without express or implied warranty. * * THOMAS ROELL DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE, * INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN NO * EVENT SHALL THOMAS ROELL BE LIABLE FOR ANY SPECIAL, INDIRECT OR * CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, * DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER * TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR * PERFORMANCE OF THIS SOFTWARE. * * Author: Thomas Roell, roell@informatik.tu-muenchen.de * */ #include "assyntax.h" FILE("vgaBank.s") AS_BEGIN /* * Because a modern VGA has more than 128kBytes (which are mappable into the * 386' memory some logic is required. The VGA's memory (logical VGA * address space) is devided into smaller parts (called logical segments). * These segments are mapped to logical areas. * * There are there different logical mapping areas: * * Read: an area which can be read from * Write: an area which can be written to * ReadWrite: here is both read an write possible * * It is permissable to use simultaneously a Read and a Write, but you can use * ReadWrite only as a single. * For example the bitblitting code uses a Read area as source and a Write * area as destination. Most other routines use only a ReadWrite. * * A logical mapping area is described by some parameters (here I will for * example describe a Read area: * * ReadBottom lowest accessable byte relative to the beginning of the * VGA boards mapped memory. * * ReadTop highes accessable byte plus one. * * SegmentSize size of such an mapped area (common for all three) * * SegmentShift log2(SegmentSize) (used to compute the logical segment) * * SegmentMask SegmentSize - 1 (used to mask the offset inter an area) * * * All that the following routines are doing is computing for a given offset * into the logical VGA adress space the offset into such an logical area * and the logical segment number. By the way they call also the VGA board's * driver to set up the VGA's physical memory mapping according to the logical * that was requested by the calliie. * * For shake of simplicity Write and ReadWrite share the same Bottom & Top. * NOTE: Read & Write may have differnt starting addresses, or even common. * * There are multible routines present for the same effect. This was made * for effectivly interface lowlevel assembly language best. */ /* * BUGALERT: this should be gotten from vga.h. But since there some C lang. * things, too ... */ #include "vgaAsm.h" SEG_DATA GLOBL GLNAME(writeseg) GLNAME(writeseg): D_LONG 0 GLNAME(readseg): D_LONG 0 GLNAME(saveseg): D_LONG 0 SEG_TEXT /* *----------------------------------------------------------------------- * vgaSetReadWrite --- * select a memory bank of the VGA board for read & write access * Results: * The adjusted pointer into the memory. * * Side Effects: * None. *----------------------------------------------------------------------- * pointer * vgaSetReadWrite(p) * register pointer p; * { * #ifdef XF86VGA16 * writeseg = ((unsigned long)p - vgaBase) >> vgaSegmentShift; * (vgaSetReadWriteFunc)(writeseg); * return (vgaWriteBottom + (((unsigned int)p - vgaBase) & vgaSegmentMask)); * #else * writeseg = ((unsigned long)p - VGABASE) >> vgaSegmentShift; * (vgaSetReadWriteFunc)(writeseg); * return (vgaWriteBottom + ((unsigned int)p & vgaSegmentMask)); * #endif * } * */ ALIGNTEXT4 GLOBL GLNAME(vgaSetReadWrite) GLNAME(vgaSetReadWrite): MOV_L (REGOFF(4,ESP),EAX) PUSH_L (ECX) PUSH_L (EDX) #ifdef XF86VGA16 SUB_L (CONTENT(GLNAME(vgaBase)),EAX) #else SUB_L (VGABASE,EAX) #endif MOV_L (CONTENT(GLNAME(vgaSegmentShift)),ECX) SHR_L (CL,EAX) MOV_L (EAX,CONTENT(GLNAME(writeseg))) MOV_L (CONTENT(GLNAME(vgaSetReadWriteFunc)),EDX) CALL (CODEPTR(EDX)) POP_L (EDX) POP_L (ECX) MOV_L (REGOFF(4,ESP),EAX) #ifdef XF86VGA16 SUB_L (CONTENT(GLNAME(vgaBase)),EAX) #endif AND_L (CONTENT(GLNAME(vgaSegmentMask)),EAX) ADD_L (CONTENT(GLNAME(vgaWriteBottom)),EAX) RET /* *----------------------------------------------------------------------- * vgaReadWriteNext --- * switch to next memory bank of the VGA board for read & write access * Results: * The adjusted pointer into the memory. * * Side Effects: * None. *----------------------------------------------------------------------- * * * pointer * vgaReadWriteNext(p) * register pointer p; * { * (vgaSetReadWriteFunc)(++writeseg); * return (p - vgaSegmentSize); * } */ ALIGNTEXT4 GLOBL GLNAME(vgaReadWriteNext) GLNAME(vgaReadWriteNext): PUSH_L (EDX) MOV_L (CONTENT(GLNAME(writeseg)),EAX) INC_L (EAX) MOV_L (EAX,CONTENT(GLNAME(writeseg))) MOV_L (CONTENT(GLNAME(vgaSetReadWriteFunc)),EDX) CALL (CODEPTR(EDX)) POP_L (EDX) MOV_L (REGOFF(4,ESP),EAX) SUB_L (CONTENT(GLNAME(vgaSegmentSize)),EAX) RET /* *----------------------------------------------------------------------- * vgaReadWritePrev --- * switch to previous memory bank of the VGA board for read & write access * Results: * The adjusted pointer into the memory. * * Side Effects: * None. *----------------------------------------------------------------------- * * pointer * vgaReadWritePrev(p) * register pointer p; * { * (vgaSetReadWriteFunc)(--writeseg); * return (p + vgaSegmentSize); * } */ ALIGNTEXT4 GLOBL GLNAME(vgaReadWritePrev) GLNAME(vgaReadWritePrev): PUSH_L (EDX) MOV_L (CONTENT(GLNAME(writeseg)),EAX) DEC_L (EAX) MOV_L (EAX,CONTENT(GLNAME(writeseg))) MOV_L (CONTENT(GLNAME(vgaSetReadWriteFunc)),EDX) CALL (CODEPTR(EDX)) POP_L (EDX) MOV_L (REGOFF(4,ESP),EAX) ADD_L (CONTENT(GLNAME(vgaSegmentSize)),EAX) RET /* *----------------------------------------------------------------------- * vgaSetRead --- * select a memory bank of the VGA board for read access * Results: * The adjusted pointer into the memory. * * Side Effects: * None. *----------------------------------------------------------------------- * pointer * vgaSetRead(p) * register pointer p; * { * #ifdef XF86VGA16 * readseg = ((unsigned long)p - vgaBase) >> vgaSegmentShift; * (vgaSetReadFunc)(readseg); * return (vgaReadBottom + (((unsigned int)p - vgaBase) & vgaSegmentMask)); * #else * readseg = ((unsigned long)p - VGABASE) >> vgaSegmentShift; * (vgaSetReadFunc)(readseg); * return (vgaReadBottom + ((unsigned int)p & vgaSegmentMask)); * #endif * } * */ ALIGNTEXT4 GLOBL GLNAME(vgaSetRead) GLNAME(vgaSetRead): MOV_L (REGOFF(4,ESP),EAX) PUSH_L (ECX) PUSH_L (EDX) #ifdef XF86VGA16 SUB_L (CONTENT(GLNAME(vgaBase)),EAX) #else SUB_L (VGABASE,EAX) #endif MOV_L (CONTENT(GLNAME(vgaSegmentShift)),ECX) SHR_L (CL,EAX) MOV_L (EAX,CONTENT(GLNAME(readseg))) MOV_L (CONTENT(GLNAME(vgaSetReadFunc)),EDX) CALL (CODEPTR(EDX)) POP_L (EDX) POP_L (ECX) MOV_L (REGOFF(4,ESP),EAX) #ifdef XF86VGA16 SUB_L (CONTENT(GLNAME(vgaBase)),EAX) #endif AND_L (CONTENT(GLNAME(vgaSegmentMask)),EAX) ADD_L (CONTENT(GLNAME(vgaReadBottom)),EAX) RET /* *----------------------------------------------------------------------- * vgaReadNext --- * switch to next memory bank of the VGA board for read access * Results: * The adjusted pointer into the memory. * * Side Effects: * None. *----------------------------------------------------------------------- * * * pointer * vgaReadNext(p) * register pointer p; * { * (vgaSetReadFunc)(++readseg); * return (p - vgaSegmentSize); * } */ ALIGNTEXT4 GLOBL GLNAME(vgaReadNext) GLNAME(vgaReadNext): PUSH_L (EDX) MOV_L (CONTENT(GLNAME(readseg)),EAX) INC_L (EAX) MOV_L (EAX,CONTENT(GLNAME(readseg))) MOV_L (CONTENT(GLNAME(vgaSetReadFunc)),EDX) CALL (CODEPTR(EDX)) POP_L (EDX) MOV_L (REGOFF(4,ESP),EAX) SUB_L (CONTENT(GLNAME(vgaSegmentSize)),EAX) RET /* *----------------------------------------------------------------------- * vgaReadPrev --- * switch to previous memory bank of the VGA board for read access * Results: * The adjusted pointer into the memory. * * Side Effects: * None. *----------------------------------------------------------------------- * * pointer * vgaReadPrev(p) * register pointer p; * { * (vgaSetReadFunc)(--readseg); * return (p + vgaSegmentSize); * } */ ALIGNTEXT4 GLOBL GLNAME(vgaReadPrev) GLNAME(vgaReadPrev): PUSH_L (EDX) MOV_L (CONTENT(GLNAME(readseg)),EAX) DEC_L (EAX) MOV_L (EAX,CONTENT(GLNAME(readseg))) MOV_L (CONTENT(GLNAME(vgaSetReadFunc)),EDX) CALL (CODEPTR(EDX)) POP_L (EDX) MOV_L (REGOFF(4,ESP),EAX) ADD_L (CONTENT(GLNAME(vgaSegmentSize)),EAX) RET /* *----------------------------------------------------------------------- * vgaSetWrite --- * select a memory bank of the VGA board for write access * Results: * The adjusted pointer into the memory. * * Side Effects: * None. *----------------------------------------------------------------------- * pointer * vgaSetWrite(p) * register pointer p; * { * #ifdef XF86VGA16 * writeseg = ((unsigned long)p - vgaBase) >> vgaSegmentShift; * (vgaSetWriteFunc)(writeseg); * return (vgaWriteBottom + (((unsigned int)p - vgaBase) & vgaSegmentMask)); * #else * writeseg = ((unsigned long)p - VGABASE) >> vgaSegmentShift; * (vgaSetWriteFunc)(writeseg); * return (vgaWriteBottom + ((unsigned int)p & vgaSegmentMask)); * #endif * } * */ ALIGNTEXT4 GLOBL GLNAME(vgaSetWrite) GLNAME(vgaSetWrite): MOV_L (REGOFF(4,ESP),EAX) PUSH_L (ECX) PUSH_L (EDX) #ifdef XF86VGA16 SUB_L (CONTENT(GLNAME(vgaBase)),EAX) #else SUB_L (VGABASE,EAX) #endif MOV_L (CONTENT(GLNAME(vgaSegmentShift)),ECX) SHR_L (CL,EAX) MOV_L (EAX,CONTENT(GLNAME(writeseg))) MOV_L (CONTENT(GLNAME(vgaSetWriteFunc)),EDX) CALL (CODEPTR(EDX)) POP_L (EDX) POP_L (ECX) MOV_L (REGOFF(4,ESP),EAX) #ifdef XF86VGA16 SUB_L (CONTENT(GLNAME(vgaBase)),EAX) #endif AND_L (CONTENT(GLNAME(vgaSegmentMask)),EAX) ADD_L (CONTENT(GLNAME(vgaWriteBottom)),EAX) RET /* *----------------------------------------------------------------------- * vgaWriteNext --- * switch to next memory bank of the VGA board for write access * Results: * The adjusted pointer into the memory. * * Side Effects: * None. *----------------------------------------------------------------------- * * * pointer * vgaWriteNext(p) * register pointer p; * { * (vgaSetWriteFunc)(++writeseg); * return (p - vgaSegmentSize); * } */ ALIGNTEXT4 GLOBL GLNAME(vgaWriteNext) GLNAME(vgaWriteNext): PUSH_L (EDX) MOV_L (CONTENT(GLNAME(writeseg)),EAX) INC_L (EAX) MOV_L (EAX,CONTENT(GLNAME(writeseg))) MOV_L (CONTENT(GLNAME(vgaSetWriteFunc)),EDX) CALL (CODEPTR(EDX)) POP_L (EDX) MOV_L (REGOFF(4,ESP),EAX) SUB_L (CONTENT(GLNAME(vgaSegmentSize)),EAX) RET /* *----------------------------------------------------------------------- * vgaWritePrev --- * switch to previous memory bank of the VGA board for write access * Results: * The adjusted pointer into the memory. * * Side Effects: * None. *----------------------------------------------------------------------- * * pointer * vgaWritePrev(p) * register pointer p; * { * (vgaSetWriteFunc)(--writeseg); * return (p + vgaSegmentSize); * } */ ALIGNTEXT4 GLOBL GLNAME(vgaWritePrev) GLNAME(vgaWritePrev): PUSH_L (EDX) MOV_L (CONTENT(GLNAME(writeseg)),EAX) DEC_L (EAX) MOV_L (EAX,CONTENT(GLNAME(writeseg))) MOV_L (CONTENT(GLNAME(vgaSetWriteFunc)),EDX) CALL (CODEPTR(EDX)) POP_L (EDX) MOV_L (REGOFF(4,ESP),EAX) ADD_L (CONTENT(GLNAME(vgaSegmentSize)),EAX) RET /* *----------------------------------------------------------------------- * vgaSaveBank -- * save Banking-state * Results: * None. * * Side Effects: * None. *----------------------------------------------------------------------- * * void * vgaSaveBank() * { * saveseg = writeseg; * } */ ALIGNTEXT4 GLOBL GLNAME(vgaSaveBank) GLNAME(vgaSaveBank): MOV_L (CONTENT(GLNAME(writeseg)),EAX) MOV_L (EAX,CONTENT(GLNAME(saveseg))) RET /* *----------------------------------------------------------------------- * vgaRestoreBank -- * restore the banking after vgaSaveBank was called * * Results: * None. * * Side Effects: * None. *----------------------------------------------------------------------- * * void * vgaRestoreBank() * { * (vgaSetWriteFunc)(saveseg); * (vgaSetReadFunc)(saveseg); * } */ ALIGNTEXT4 GLOBL GLNAME(vgaRestoreBank) GLNAME(vgaRestoreBank): PUSH_L (EDX) MOV_L (CONTENT(GLNAME(saveseg)),EAX) MOV_L (EAX,CONTENT(GLNAME(writeseg))) MOV_L (CONTENT(GLNAME(vgaSetWriteFunc)),EDX) CALL (CODEPTR(EDX)) MOV_L (CONTENT(GLNAME(saveseg)),EAX) MOV_L (EAX,CONTENT(GLNAME(readseg))) MOV_L (CONTENT(GLNAME(vgaSetReadFunc)),EDX) CALL (CODEPTR(EDX)) POP_L (EDX) RET /* *----------------------------------------------------------------------- * vgaPushRead --- * make the write-bank also readable. no acces to the former read bank ! * Results: * None. * * Side Effects: * None. *----------------------------------------------------------------------- * * void * vgaPushRead(p) * { * (vgaSetReadWriteFunc)(writeseg); * } */ ALIGNTEXT4 GLOBL GLNAME(vgaPushRead) GLNAME(vgaPushRead): PUSH_L (EDX) MOV_L (CONTENT(GLNAME(writeseg)),EAX) MOV_L (CONTENT(GLNAME(vgaSetReadWriteFunc)),EDX) CALL (CODEPTR(EDX)) POP_L (EDX) RET /* *----------------------------------------------------------------------- * vgaPopRead --- * restore the banking after vgaPushRead was called * * Results: * None. * * Side Effects: * None. *----------------------------------------------------------------------- * * void * vgaPopRead(p) * { * (vgaSetWriteFunc)(writeseg); * (vgaSetReadFunc)(readseg); * } */ ALIGNTEXT4 GLOBL GLNAME(vgaPopRead) GLNAME(vgaPopRead): PUSH_L (EDX) MOV_L (CONTENT(GLNAME(writeseg)),EAX) MOV_L (CONTENT(GLNAME(vgaSetWriteFunc)),EDX) CALL (CODEPTR(EDX)) MOV_L (CONTENT(GLNAME(readseg)),EAX) MOV_L (CONTENT(GLNAME(vgaSetReadFunc)),EDX) CALL (CODEPTR(EDX)) POP_L (EDX) RET