+++ /dev/null
-/*
- Implementation of DMA routines on DOS
- Copyright (C) 1999 by Andrew Zabolotny, <bit@eltech.ru>
-
- This library is free software; you can redistribute it and/or
- modify it under the terms of the GNU Library General Public
- License as published by the Free Software Foundation; either
- version 2 of the License, or (at your option) any later version.
-
- This library is distributed in the hope that it will be useful,
- but WITHOUT ANY WARRANTY; without even the implied warranty of
- MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
- Library General Public License for more details.
-
- You should have received a copy of the GNU Library General Public
- License along with this library; if not, write to the Free
- Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
-*/
-
-#include "dosdma.h"
-
-#include <go32.h> /* includes sys/version.h (djgpp >= 2.02) */
-#include <dos.h>
-#include <dpmi.h>
-#include <sys/nearptr.h>
-#include <malloc.h>
-#include "mikmod.h" /* for MikMod_malloc() & co */
-
-/* BUG WARNING: there is an error in DJGPP libraries <= 2.01:
- * src/libc/dpmi/api/d0102.s loads the selector and allocsize
- * arguments in the wrong order. DJGPP >= 2.02 have it fixed. */
-#if (!defined(__DJGPP_MINOR__) || (__DJGPP_MINOR__+0) < 2)
-#warning __dpmi_resize_dos_memory() from DJGPP <= 2.01 is broken!
-#endif
-
-__dma_regs dma[8] = {
-/* *INDENT-OFF* */
- {DMA_ADDR_0, DMA_PAGE_0, DMA_SIZE_0,
- DMA1_MASK_REG, DMA1_CLEAR_FF_REG, DMA1_MODE_REG},
- {DMA_ADDR_1, DMA_PAGE_1, DMA_SIZE_1,
- DMA1_MASK_REG, DMA1_CLEAR_FF_REG, DMA1_MODE_REG},
-
- {DMA_ADDR_2, DMA_PAGE_2, DMA_SIZE_2,
- DMA1_MASK_REG, DMA1_CLEAR_FF_REG, DMA1_MODE_REG},
- {DMA_ADDR_3, DMA_PAGE_3, DMA_SIZE_3,
- DMA1_MASK_REG, DMA1_CLEAR_FF_REG, DMA1_MODE_REG},
-
- {DMA_ADDR_4, 0, DMA_SIZE_4,
- DMA2_MASK_REG, DMA2_CLEAR_FF_REG, DMA2_MODE_REG},
- {DMA_ADDR_5, DMA_PAGE_5, DMA_SIZE_5,
- DMA2_MASK_REG, DMA2_CLEAR_FF_REG, DMA2_MODE_REG},
-
- {DMA_ADDR_6, DMA_PAGE_6, DMA_SIZE_6,
- DMA2_MASK_REG, DMA2_CLEAR_FF_REG, DMA2_MODE_REG},
- {DMA_ADDR_7, DMA_PAGE_7, DMA_SIZE_7,
- DMA2_MASK_REG, DMA2_CLEAR_FF_REG, DMA2_MODE_REG}
-/* *INDENT-ON* */
-};
-
-static int __initialized = 0;
-static int __buffer_count = 0;
-static __dpmi_meminfo __locked_data;
-
-int dma_initialize()
-{
- if (!__djgpp_nearptr_enable())
- return 0;
-
- /* Trick: Avoid re-setting DS selector limit on each memory allocation
- call */
- __djgpp_selector_limit = 0xffffffff;
-
- __locked_data.address = __djgpp_base_address + (unsigned long)&dma;
- __locked_data.size = sizeof(dma);
- if (__dpmi_lock_linear_region(&__locked_data))
- return 0;
-
- return (__initialized = 1);
-}
-
-void dma_finalize()
-{
- if (!__initialized)
- return;
- __dpmi_unlock_linear_region(&__locked_data);
- __djgpp_nearptr_disable();
-}
-
-dma_buffer *dma_allocate(unsigned int channel, unsigned int size)
-{
- int parsize = (size + 15) >> 4; /* size in paragraphs */
- int par = 0; /* Real-mode paragraph */
- int selector = 0; /* Protected-mode selector */
- int mask = channel <= 3 ? 0xfff : 0x1fff; /* Alignment mask in para. */
- int allocsize = parsize; /* Allocated size in paragraphs */
- int count; /* Try count */
- int bound = 0; /* Nearest bound address */
- int maxsize; /* Maximal possible block size */
- dma_buffer *buffer = NULL;
- __dpmi_meminfo buff_info, struct_info;
-
- if (!dma_initialize())
- return NULL;
-
- /* Loop until we'll get a properly aligned memory block */
- for (count = 8; count; count--) {
- int resize = (selector != 0);
-
- /* Try first to resize (possibly previously) allocated block */
- if (resize) {
- maxsize = (bound + parsize) - par;
- if (maxsize > parsize * 2)
- maxsize = parsize * 2;
- if (maxsize == allocsize)
- resize = 0;
- else {
- allocsize = maxsize;
- if (__dpmi_resize_dos_memory(selector, allocsize, &maxsize) !=
- 0) resize = 0;
- }
- }
-
- if (!resize) {
- if (selector)
- __dpmi_free_dos_memory(selector), selector = 0;
- par = __dpmi_allocate_dos_memory(allocsize, &selector);
- }
-
- if ((par == 0) || (par == -1))
- goto exit;
-
- /* If memory block contains a properly aligned portion, quit loop */
- bound = (par + mask + 1) & ~mask;
- if (par + parsize <= bound)
- break;
- if (bound + parsize <= par + allocsize) {
- par = bound;
- break;
- }
- }
- if (!count) {
- __dpmi_free_dos_memory(selector);
- goto exit;
- }
-
- buffer = (dma_buffer *) MikMod_malloc(sizeof(dma_buffer));
- buffer->linear = (unsigned char *)(__djgpp_conventional_base + bound * 16);
- buffer->physical = bound * 16;
- buffer->size = parsize * 16;
- buffer->selector = selector;
- buffer->channel = channel;
-
- buff_info.address = buffer->physical;
- buff_info.size = buffer->size;
- /*
- Don't pay attention to return code since under plain DOS it often
- returns error (at least under HIMEM/CWSDPMI and EMM386/DPMI)
- */
- __dpmi_lock_linear_region(&buff_info);
-
- /* Lock the DMA buffer control structure as well */
- struct_info.address = __djgpp_base_address + (unsigned long)buffer;
- struct_info.size = sizeof(dma_buffer);
- if (__dpmi_lock_linear_region(&struct_info)) {
- __dpmi_unlock_linear_region(&buff_info);
- __dpmi_free_dos_memory(selector);
- MikMod_free(buffer);
- buffer = NULL;
- goto exit;
- }
-
- exit:
- if (buffer)
- __buffer_count++;
- else if (--__buffer_count == 0)
- dma_finalize();
- return buffer;
-}
-
-void dma_free(dma_buffer * buffer)
-{
- __dpmi_meminfo buff_info;
-
- if (!buffer)
- return;
-
- buff_info.address = buffer->physical;
- buff_info.size = buffer->size;
- __dpmi_unlock_linear_region(&buff_info);
-
- __dpmi_free_dos_memory(buffer->selector);
- MikMod_free(buffer);
-
- if (--__buffer_count == 0)
- dma_finalize();
-}
-
-void dma_start(dma_buffer * buffer, unsigned long count, unsigned char mode)
-{
- /* Disable interrupts */
- int old_ints = disable();
- dma_disable(buffer->channel);
- dma_set_mode(buffer->channel, mode);
- dma_clear_ff(buffer->channel);
- dma_set_addr(buffer->channel, buffer->physical);
- dma_clear_ff(buffer->channel);
- dma_set_count(buffer->channel, count);
- dma_enable(buffer->channel);
- /* Re-enable interrupts */
- if (old_ints)
- enable();
-}
-
-/* ex:set ts=4: */
projects / dosdemo / blobdiff