amifb.c

Linux环境下视频显示卡设备的驱动程序源代码

		if (dst_idx+n <= BITS_PER_LONG) {
			// Single destination word
			if (last)
				first &= last;
			if (shift > 0) {
				// Single source word
				*dst = comp(*src >> right, *dst, first);
			} else if (src_idx+n <= BITS_PER_LONG) {
				// Single source word
				*dst = comp(*src << left, *dst, first);
			} else {
				// 2 source words
				d0 = *src++;
				d1 = *src;
				*dst = comp(d0 << left | d1 >> right, *dst,
					    first);
			}
		} else {
			// Multiple destination words
			d0 = *src++;
			// Leading bits
			if (shift > 0) {
				// Single source word
				*dst = comp(d0 >> right, *dst, first);
				dst++;
				n -= BITS_PER_LONG-dst_idx;
			} else {
				// 2 source words
				d1 = *src++;
				*dst = comp(d0 << left | d1 >> right, *dst,
					    first);
				d0 = d1;
				dst++;
				n -= BITS_PER_LONG-dst_idx;
			}

			// Main chunk
			m = n % BITS_PER_LONG;
			n /= BITS_PER_LONG;
			while (n >= 4) {
				d1 = *src++;
				*dst++ = d0 << left | d1 >> right;
				d0 = d1;
				d1 = *src++;
				*dst++ = d0 << left | d1 >> right;
				d0 = d1;
				d1 = *src++;
				*dst++ = d0 << left | d1 >> right;
				d0 = d1;
				d1 = *src++;
				*dst++ = d0 << left | d1 >> right;
				d0 = d1;
				n -= 4;
			}
			while (n--) {
				d1 = *src++;
				*dst++ = d0 << left | d1 >> right;
				d0 = d1;
			}

			// Trailing bits
			if (last) {
				if (m <= right) {
					// Single source word
					*dst = comp(d0 << left, *dst, last);
				} else {
					// 2 source words
					d1 = *src;
					*dst = comp(d0 << left | d1 >> right,
						    *dst, last);
				}
			}
		}
	}
}


    /*
     *  Unaligned reverse bit copy using 32-bit or 64-bit memory accesses
     */

static void bitcpy_rev(unsigned long *dst, int dst_idx,
		       const unsigned long *src, int src_idx, u32 n)
{
	unsigned long first, last;
	int shift = dst_idx-src_idx, left, right;
	unsigned long d0, d1;
	int m;

	if (!n)
		return;

	dst += (n-1)/BITS_PER_LONG;
	src += (n-1)/BITS_PER_LONG;
	if ((n-1) % BITS_PER_LONG) {
		dst_idx += (n-1) % BITS_PER_LONG;
		dst += dst_idx >> SHIFT_PER_LONG;
		dst_idx &= BITS_PER_LONG-1;
		src_idx += (n-1) % BITS_PER_LONG;
		src += src_idx >> SHIFT_PER_LONG;
		src_idx &= BITS_PER_LONG-1;
	}

	shift = dst_idx-src_idx;
	first = ~0UL << (BITS_PER_LONG-1-dst_idx);
	last = ~(~0UL << (BITS_PER_LONG-1-((dst_idx-n) % BITS_PER_LONG)));

	if (!shift) {
		// Same alignment for source and dest

		if ((unsigned long)dst_idx+1 >= n) {
			// Single word
			if (last)
				first &= last;
			*dst = comp(*src, *dst, first);
		} else {
			// Multiple destination words
			// Leading bits
			if (first) {
				*dst = comp(*src, *dst, first);
				dst--;
				src--;
				n -= dst_idx+1;
			}

			// Main chunk
			n /= BITS_PER_LONG;
			while (n >= 8) {
				*dst-- = *src--;
				*dst-- = *src--;
				*dst-- = *src--;
				*dst-- = *src--;
				*dst-- = *src--;
				*dst-- = *src--;
				*dst-- = *src--;
				*dst-- = *src--;
				n -= 8;
			}
			while (n--)
				*dst-- = *src--;

			// Trailing bits
			if (last)
				*dst = comp(*src, *dst, last);
		}
	} else {
		// Different alignment for source and dest

		right = shift & (BITS_PER_LONG-1);
		left = -shift & (BITS_PER_LONG-1);

		if ((unsigned long)dst_idx+1 >= n) {
			// Single destination word
			if (last)
				first &= last;
			if (shift < 0) {
				// Single source word
				*dst = comp(*src << left, *dst, first);
			} else if (1+(unsigned long)src_idx >= n) {
				// Single source word
				*dst = comp(*src >> right, *dst, first);
			} else {
				// 2 source words
				d0 = *src--;
				d1 = *src;
				*dst = comp(d0 >> right | d1 << left, *dst,
					    first);
			}
		} else {
			// Multiple destination words
			d0 = *src--;
			// Leading bits
			if (shift < 0) {
				// Single source word
				*dst = comp(d0 << left, *dst, first);
				dst--;
				n -= dst_idx+1;
			} else {
				// 2 source words
				d1 = *src--;
				*dst = comp(d0 >> right | d1 << left, *dst,
					    first);
				d0 = d1;
				dst--;
				n -= dst_idx+1;
			}

			// Main chunk
			m = n % BITS_PER_LONG;
			n /= BITS_PER_LONG;
			while (n >= 4) {
				d1 = *src--;
				*dst-- = d0 >> right | d1 << left;
				d0 = d1;
				d1 = *src--;
				*dst-- = d0 >> right | d1 << left;
				d0 = d1;
				d1 = *src--;
				*dst-- = d0 >> right | d1 << left;
				d0 = d1;
				d1 = *src--;
				*dst-- = d0 >> right | d1 << left;
				d0 = d1;
				n -= 4;
			}
			while (n--) {
				d1 = *src--;
				*dst-- = d0 >> right | d1 << left;
				d0 = d1;
			}

			// Trailing bits
			if (last) {
				if (m <= left) {
					// Single source word
					*dst = comp(d0 >> right, *dst, last);
				} else {
					// 2 source words
					d1 = *src;
					*dst = comp(d0 >> right | d1 << left,
						    *dst, last);
				}
			}
		}
	}
}


    /*
     *  Unaligned forward inverting bit copy using 32-bit or 64-bit memory
     *  accesses
     */

static void bitcpy_not(unsigned long *dst, int dst_idx,
		       const unsigned long *src, int src_idx, u32 n)
{
	unsigned long first, last;
	int shift = dst_idx-src_idx, left, right;
	unsigned long d0, d1;
	int m;

	if (!n)
		return;

	shift = dst_idx-src_idx;
	first = ~0UL >> dst_idx;
	last = ~(~0UL >> ((dst_idx+n) % BITS_PER_LONG));

	if (!shift) {
		// Same alignment for source and dest

		if (dst_idx+n <= BITS_PER_LONG) {
			// Single word
			if (last)
				first &= last;
			*dst = comp(~*src, *dst, first);
		} else {
			// Multiple destination words
			// Leading bits
			if (first) {
				*dst = comp(~*src, *dst, first);
				dst++;
				src++;
				n -= BITS_PER_LONG-dst_idx;
			}

			// Main chunk
			n /= BITS_PER_LONG;
			while (n >= 8) {
				*dst++ = ~*src++;
				*dst++ = ~*src++;
				*dst++ = ~*src++;
				*dst++ = ~*src++;
				*dst++ = ~*src++;
				*dst++ = ~*src++;
				*dst++ = ~*src++;
				*dst++ = ~*src++;
				n -= 8;
			}
			while (n--)
				*dst++ = ~*src++;

			// Trailing bits
			if (last)
				*dst = comp(~*src, *dst, last);
		}
	} else {
		// Different alignment for source and dest

		right = shift & (BITS_PER_LONG-1);
		left = -shift & (BITS_PER_LONG-1);

		if (dst_idx+n <= BITS_PER_LONG) {
			// Single destination word
			if (last)
				first &= last;
			if (shift > 0) {
				// Single source word
				*dst = comp(~*src >> right, *dst, first);
			} else if (src_idx+n <= BITS_PER_LONG) {
				// Single source word
				*dst = comp(~*src << left, *dst, first);
			} else {
				// 2 source words
				d0 = ~*src++;
				d1 = ~*src;
				*dst = comp(d0 << left | d1 >> right, *dst,
					    first);
			}
		} else {
			// Multiple destination words
			d0 = ~*src++;
			// Leading bits
			if (shift > 0) {
				// Single source word
				*dst = comp(d0 >> right, *dst, first);
				dst++;
				n -= BITS_PER_LONG-dst_idx;
			} else {
				// 2 source words
				d1 = ~*src++;
				*dst = comp(d0 << left | d1 >> right, *dst,
					    first);
				d0 = d1;
				dst++;
				n -= BITS_PER_LONG-dst_idx;
			}

			// Main chunk
			m = n % BITS_PER_LONG;
			n /= BITS_PER_LONG;
			while (n >= 4) {
				d1 = ~*src++;
				*dst++ = d0 << left | d1 >> right;
				d0 = d1;
				d1 = ~*src++;
				*dst++ = d0 << left | d1 >> right;
				d0 = d1;
				d1 = ~*src++;
				*dst++ = d0 << left | d1 >> right;
				d0 = d1;
				d1 = ~*src++;
				*dst++ = d0 << left | d1 >> right;
				d0 = d1;
				n -= 4;
			}
			while (n--) {
				d1 = ~*src++;
				*dst++ = d0 << left | d1 >> right;
				d0 = d1;
			}

			// Trailing bits
			if (last) {
				if (m <= right) {
					// Single source word
					*dst = comp(d0 << left, *dst, last);
				} else {
					// 2 source words
					d1 = ~*src;
					*dst = comp(d0 << left | d1 >> right,
						    *dst, last);
				}
			}
		}
	}
}


    /*
     *  Unaligned 32-bit pattern fill using 32/64-bit memory accesses
     */

static void bitfill32(unsigned long *dst, int dst_idx, u32 pat, u32 n)
{
	unsigned long val = pat;
	unsigned long first, last;

	if (!n)
		return;

#if BITS_PER_LONG == 64
	val |= val << 32;
#endif

	first = ~0UL >> dst_idx;
	last = ~(~0UL >> ((dst_idx+n) % BITS_PER_LONG));

	if (dst_idx+n <= BITS_PER_LONG) {
		// Single word
		if (last)
			first &= last;
		*dst = comp(val, *dst, first);
	} else {
		// Multiple destination words
		// Leading bits
		if (first) {
			*dst = comp(val, *dst, first);
			dst++;
			n -= BITS_PER_LONG-dst_idx;
		}

		// Main chunk
		n /= BITS_PER_LONG;
		while (n >= 8) {
			*dst++ = val;
			*dst++ = val;
			*dst++ = val;
			*dst++ = val;
			*dst++ = val;
			*dst++ = val;
			*dst++ = val;
			*dst++ = val;
			n -= 8;
		}
		while (n--)
			*dst++ = val;

		// Trailing bits
		if (last)
			*dst = comp(val, *dst, last);
	}
}


    /*
     *  Unaligned 32-bit pattern xor using 32/64-bit memory accesses
     */

static void bitxor32(unsigned long *dst, int dst_idx, u32 pat, u32 n)
{
	unsigned long val = pat;
	unsigned long first, last;

	if (!n)
		return;

#if BITS_PER_LONG == 64
	val |= val << 32;
#endif

	first = ~0UL >> dst_idx;
	last = ~(~0UL >> ((dst_idx+n) % BITS_PER_LONG));

	if (dst_idx+n <= BITS_PER_LONG) {
		// Single word
		if (last)
			first &= last;
		*dst = xor(val, *dst, first);
	} else {
		// Multiple destination words
		// Leading bits
		if (first) {
			*dst = xor(val, *dst, first);
			dst++;
			n -= BITS_PER_LONG-dst_idx;
		}

		// Main chunk
		n /= BITS_PER_LONG;
		while (n >= 4) {
			*dst++ ^= val;
			*dst++ ^= val;
			*dst++ ^= val;
			*dst++ ^= val;
			n -= 4;
		}
		while (n--)
			*dst++ ^= val;

		// Trailing bits
		if (last)
			*dst = xor(val, *dst, last);
	}
}

static inline void fill_one_line(int bpp, unsigned long next_plane,
				 unsigned long *dst, int dst_idx, u32 n,
				 u32 color)
{