Mercurial > sos > sos
changeset 22:3fb0ec050ff3
malloc has been restructured to now work in a more logical manner
malloc now allocates memory from the beginning of a block instead of the end.
Additionally, memory is now 8-byte aligned instead of 16-byte aligned.
malloc_init should now be called to set up all the memory information.
Fixed a bug where malloc would not have iterated to find new memory locations.
| author | Jonathan Pevarnek <pevarnj@gmail.com> |
|---|---|
| date | Wed, 16 Mar 2011 00:09:35 -0400 |
| parents | 7c2adb65ceac |
| children | f68b59af5ea6 |
| files | arch/io.c include/std.h src/init.c src/std.c |
| diffstat | 4 files changed, 28 insertions(+), 27 deletions(-) [+] |
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--- a/arch/io.c Tue Mar 15 22:55:36 2011 -0400 +++ b/arch/io.c Wed Mar 16 00:09:35 2011 -0400 @@ -178,7 +178,6 @@ /* console I/O functions */ -#define CON_LEN 132 #define CON_DEV 0x0009 struct pmcw {
--- a/include/std.h Tue Mar 15 22:55:36 2011 -0400 +++ b/include/std.h Wed Mar 16 00:09:35 2011 -0400 @@ -19,15 +19,13 @@ //MALLOC CODE -union block { - struct { - union block *next; - unsigned int size; - } s; - double foo; +struct block{ + struct block *next; + unsigned int size; }; -typedef union block Block; +typedef struct block Block; +void malloc_init(size_t memSize); void* malloc(size_t size); //void free(void *ptr);
--- a/src/init.c Tue Mar 15 22:55:36 2011 -0400 +++ b/src/init.c Wed Mar 16 00:09:35 2011 -0400 @@ -24,12 +24,13 @@ int i, n; char *buffer; char input[30]; + malloc_init(0x1400000); //20MB memory while(1) { sPrint("How long do you want the string? "); n = atoi(sGet(input, 30)); - buffer = (char*) malloc(n + 2); + buffer = (char*) malloc(n); if (!buffer) { //allocation failed, too large sPrint("ERROR\n"); break; @@ -41,8 +42,8 @@ // dumpBuffer(buffer, n); - sPrint(append(itoa((int)buffer, input), "\n")); - sPrint(append(buffer, "\n")); + sPrint(append(itoa((unsigned long)buffer, input), "\n")); + sPrint(buffer), sPrint("\n"); } /* struct Stack theStack;
--- a/src/std.c Tue Mar 15 22:55:36 2011 -0400 +++ b/src/std.c Wed Mar 16 00:09:35 2011 -0400 @@ -128,26 +128,29 @@ static Block *allocp = NULL; //the location of the last item allocated by malloc +void malloc_init(size_t memSize) +{ + allocp = (void*)0x200000; + allocp->next = allocp; + allocp->size = memSize/sizeof(u64); +} + void* malloc(size_t size) { - unsigned int nBlocks = 1 + (size + sizeof(Block) - 1)/sizeof(Block); - //We are allocating a number of blocks equal to the number needed rounded up - //plus one for the actual info block - Block *cur, *prev; - if(allocp == NULL) { - allocp = (void*)0x200000; //this is where memory should start - allocp->s.next = allocp; - allocp->s.size = (0x1400000/sizeof(Block)); //I am going to limit the heap to 20MB for now - } + unsigned int nUnits = ((size + sizeof(Block)) + sizeof(u64) - 1)/sizeof(u64); + Block *cur, *prev, *temp; + if(allocp == NULL) return NULL; prev = allocp; - for(cur = prev->s.next;; ) { - if(cur->s.size >= nBlocks) { //this section is pretty much exactly copied from K&R - if(cur->s.size == nBlocks) { - prev->s.next = cur->s.next; + for(cur = prev->next;; prev = cur, cur = cur->next) { + if(cur->size >= nUnits) { + if(cur->size == nUnits) { + prev->next = cur->next; } else { - cur->s.size -= nBlocks; - cur += cur->s.size; - cur->s.size = nBlocks; + temp = cur + nUnits; + temp->size = cur->size - nUnits; + temp->next = cur->next; + prev->next = temp; + cur->size = nUnits; } allocp = prev; return (void*)(cur + 1);