/* ======================================================================== */ /* BITMEM -- Bit-addressed memory routines. */ /* ======================================================================== */ #include #include #include "config.h" #include "bitmem.h" /* ======================================================================== */ /* BITREV -- Reverses the bits in a 32-bit number. */ /* ======================================================================== */ static uint_32 bitrev(uint_32 r) { r = (0xFFFF0000 & (r << 16)) | (0x0000FFFF & (r >> 16)); r = (0xFF00FF00 & (r << 8)) | (0x00FF00FF & (r >> 8)); r = (0xF0F0F0F0 & (r << 4)) | (0x0F0F0F0F & (r >> 4)); r = (0xCCCCCCCC & (r << 2)) | (0x33333333 & (r >> 2)); r = (0xAAAAAAAA & (r << 1)) | (0x55555555 & (r >> 1)); return r; } /* ======================================================================== */ /* BITMEM_CREATE -- Creates a new bit-memory object. */ /* ======================================================================== */ bitmem_t *bitmem_create (int org, int bits) { bitmem_t *mem; int words = (bits + 31) >> 5; if (org & 31) { fprintf(stderr, "Error: bitmem requires origin to be mult of 32.\n"); exit(1); } if (!(mem = CALLOC(bitmem_t, 1 )) || !(mem->data = CALLOC(uint_32, words + 2)) || !(mem->attr = CALLOC(uint_8, bits ))) { fprintf(stderr, "bitmem_create: Out of memory!\n"); exit(1); } mem->data++; /* We allow accesses to data[-1] */ mem->org = org >> 5; mem->size = words; return mem; } /* ======================================================================== */ /* BITMEM_LOAD -- Loads a memory image into a bit-memory. */ /* ======================================================================== */ #define CHUNK (1024) void bitmem_load (bitmem_t *mem, FILE *f) { uint_8 readbuf[CHUNK + 4]; int bytes, i; int short_rd = 0; uint_32 offset = 0; uint_32 word; /* -------------------------------------------------------------------- */ /* Keep reading until the file's empty or the memory's full. */ /* -------------------------------------------------------------------- */ while (offset < mem->size && (bytes = fread(readbuf, 1, CHUNK, f)) > 0) { /* ---------------------------------------------------------------- */ /* This code needs to handle arbitrary byte counts, but really */ /* wants multiples of four bytes. As written, it can't handle */ /* two short-reads in a row, if the first one was not a mult of 4. */ /* ---------------------------------------------------------------- */ if (bytes < CHUNK) { if (short_rd) { fprintf(stderr, "bitmem_load: Two short reads in a row\n"); exit(1); } short_rd |= bytes & 3; } /* ---------------------------------------------------------------- */ /* Pad the end of the buffer with zeros, in case # of bytes is */ /* not a multiple of 4. */ /* ---------------------------------------------------------------- */ readbuf[bytes ] = 0; readbuf[bytes+1] = 0; readbuf[bytes+2] = 0; readbuf[bytes+3] = 0; /* ---------------------------------------------------------------- */ /* Handle a read that read too much. */ /* ---------------------------------------------------------------- */ if ((bytes >> 2) + offset > mem->size) bytes = (mem->size - offset) << 2; /* ---------------------------------------------------------------- */ /* Put bytes together into words in big-endian order. */ /* ---------------------------------------------------------------- */ for (i = 0; i < bytes; i += 4, offset++) { word = (readbuf[i+0] << 24) | (readbuf[i+1] << 16) | (readbuf[i+2] << 8) | (readbuf[i+3] << 0); mem->data[offset] = word; } } } /* ======================================================================== */ /* Handy macros which are very useful for bitstream assembly. */ /* These handle the case of shifts by more than 32, which is important. */ /* ======================================================================== */ #define LSHIFT(d,s) (((s) & 32) == 0 ? (d) << (s) : 0) #define RSHIFT(d,s) (((s) & 32) == 0 ? (d) >> (s) : 0) /* ======================================================================== */ /* BITMEM_READ_FWD -- Read a bit field in the forward direction. */ /* ======================================================================== */ uint_32 bitmem_read_fwd(bitmem_t *mem, uint_32 addr, int bits) { int offset, lshift, rshift; uint_32 data; /* -------------------------------------------------------------------- */ /* Calculate our offset and shift values from the bit-address. */ /* -------------------------------------------------------------------- */ offset = addr >> 5; lshift = addr & 31; rshift = 32 - lshift; /* -------------------------------------------------------------------- */ /* Adjust our offset according to our origin. If the offset is */ /* totally outside our memory, return 0. */ /* -------------------------------------------------------------------- */ offset -= mem->org; if (offset < -1 || offset >= (int)mem->size) return 0; /* -------------------------------------------------------------------- */ /* Extract the desired data as a left-justified series of bits. */ /* -------------------------------------------------------------------- */ data = LSHIFT(mem->data[offset ], lshift) | RSHIFT(mem->data[offset + 1], rshift); /* -------------------------------------------------------------------- */ /* Shift the data right to extract the field, and return it. */ /* -------------------------------------------------------------------- */ return data >> (32 - bits); } /* ======================================================================== */ /* BITMEM_READ_FWD -- Read a bit field in the reverse direction. */ /* ======================================================================== */ uint_32 bitmem_read_rev(bitmem_t *mem, uint_32 addr, int bits) { int offset, lshift, rshift; uint_32 data; /* -------------------------------------------------------------------- */ /* Calculate our offset and shift values from the bit-address. */ /* -------------------------------------------------------------------- */ offset = addr >> 5; lshift = addr & 31; rshift = 32 - lshift; /* -------------------------------------------------------------------- */ /* Adjust our offset according to our origin. If the offset is */ /* totally outside our memory, return 0. */ /* -------------------------------------------------------------------- */ offset -= mem->org; if (offset < -1 || offset >= (int)mem->size) return 0; /* -------------------------------------------------------------------- */ /* Extract the desired data as a left-justified series of bits. */ /* -------------------------------------------------------------------- */ data = LSHIFT(mem->data[offset ], lshift) | RSHIFT(mem->data[offset + 1], rshift); /* -------------------------------------------------------------------- */ /* Mask away the bits we're not interested in with a left-mask. */ /* -------------------------------------------------------------------- */ data &= LSHIFT(~0U, 32-bits); /* -------------------------------------------------------------------- */ /* Return the bit-reversed field, right-justified. */ /* -------------------------------------------------------------------- */ return bitrev(data); } /* ======================================================================== */ /* BITMEM_SETATTR -- Set attributes on a range of memory addresses. */ /* ======================================================================== */ void bitmem_setattr (bitmem_t *mem, uint_32 addr, int len, uint_8 attr) { uint_32 org32 = mem->org << 5; /* -------------------------------------------------------------------- */ /* Never let the user set AT_LOCAL. We handle that ourselves. */ /* -------------------------------------------------------------------- */ attr &= ~AT_LOCAL; /* -------------------------------------------------------------------- */ /* Make sure address and len parameters are inside our bit-memory. */ /* Clip the arguments to the memory boundaries if necessary. */ /* -------------------------------------------------------------------- */ if (addr < org32) { len -= org32 - addr; addr = 0; } else addr -= org32; if (len < 0 || addr > (mem->size << 5)) return; if (addr + len > (mem->size << 5)) len = (mem->size << 5) - addr; /* -------------------------------------------------------------------- */ /* Step through the desired range of addresses, setting attributes. */ /* -------------------------------------------------------------------- */ while (len > 0) { mem->attr[addr++] |= attr; len--; } } /* ======================================================================== */ /* BITMEM_CLRATTR -- Clear attributes on a range of memory addresses. */ /* ======================================================================== */ void bitmem_clrattr (bitmem_t *mem, uint_32 addr, int len, uint_8 attr) { uint_32 org32 = mem->org << 5; /* -------------------------------------------------------------------- */ /* Make sure address and len parameters are inside our bit-memory. */ /* Clip the arguments to the memory boundaries if necessary. */ /* -------------------------------------------------------------------- */ if (addr < org32) { len -= org32 - addr; addr = 0; } else addr -= org32; if (len < 0 || addr > (mem->size << 5)) return; if (addr + len > (mem->size << 5)) len = (mem->size << 5) - addr; /* -------------------------------------------------------------------- */ /* Step through the desired range of addresses, clearing attributes. */ /* -------------------------------------------------------------------- */ while (len > 0) { mem->attr[addr++] &= ~attr; len--; } } /* ======================================================================== */ /* BITMEM_GETATTR -- Get merged attributes for a range of addresses. */ /* ======================================================================== */ uint_8 bitmem_getattr (bitmem_t *mem, uint_32 addr, int len) { uint_32 org32 = mem->org << 5; uint_32 size32 = mem->size << 5; uint_8 attr = AT_LOCAL; /* -------------------------------------------------------------------- */ /* Make sure address and len parameters are inside our bit-memory. */ /* Clip the arguments to the memory boundaries if necessary. */ /* -------------------------------------------------------------------- */ if (addr < org32) { len -= org32 - addr; addr = 0; } else addr -= org32; if (len <= 0 || addr >= size32) return 0; if (addr + len > size32) len = size32 - addr; /* -------------------------------------------------------------------- */ /* Step through the desired range of addresses, merging attributes. */ /* -------------------------------------------------------------------- */ while (len > 0) { attr |= mem->attr[addr++]; len--; } /* -------------------------------------------------------------------- */ /* Return the merged attribute mask. */ /* -------------------------------------------------------------------- */ return attr; } /* ======================================================================== */ /* This program is free software; you can redistribute it and/or modify */ /* it under the terms of the GNU General Public License as published by */ /* the Free Software Foundation; either version 2 of the License, or */ /* (at your option) any later version. */ /* */ /* This program 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 */ /* General Public License for more details. */ /* */ /* You should have received a copy of the GNU General Public License */ /* along with this program; if not, write to the Free Software */ /* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. */ /* ======================================================================== */ /* Copyright (c) 1998-1999, Joseph Zbiciak */ /* ======================================================================== */