Add primitive memory allocator

std/str.alc

@@ -70,3 +70,80 @@ sub str_lower
     wend
     drop
 marine
+
+[Prints a numbers as a hex string]
+[arg:int number to print]
+[ret:void]
+sub printx
+    swap
+    clone 2147483647 [32 bit signed max] > if
+        printx_64
+    else
+        clone 65535 [16 bit signed max] > if
+            printx_32
+        else
+            printx_16
+        endif
+    endif
+marine
+
+sub printx_16
+    swap
+    mem 0 + 0 itoc write
+    mem 1 + 120 write
+    mem 2 + over 12 >> 15 & itoc write
+    mem 3 + over 8 >> 15 & itoc write
+    mem 4 + over 4 >> 15 & itoc write
+    mem 5 + over 0 >> 15 & itoc write
+    mem println
+    drop
+marine
+
+sub printx_32
+    swap
+    mem 0 + 0 itoc write
+    mem 1 + 120 write
+    mem 2 + over 28 >> 15 & itoc write
+    mem 3 + over 24 >> 15 & itoc write
+    mem 4 + over 20 >> 15 & itoc write
+    mem 5 + over 16 >> 15 & itoc write
+    mem 6 + over 12 >> 15 & itoc write
+    mem 7 + over 8 >> 15 & itoc write
+    mem 8 + over 4 >> 15 & itoc write
+    mem 9 + over 0 >> 15 & itoc write
+    mem println
+    drop
+marine
+
+sub printx_64
+    swap
+    mem 0 + 0 itoc write
+    mem 1 + 120 write
+    mem 2 + over 60 >> 15 & itoc write
+    mem 3 + over 56 >> 15 & itoc write
+    mem 4 + over 52 >> 15 & itoc write
+    mem 5 + over 48 >> 15 & itoc write
+    mem 6 + over 44 >> 15 & itoc write
+    mem 7 + over 40 >> 15 & itoc write
+    mem 8 + over 36 >> 15 & itoc write
+    mem 9 + over 32 >> 15 & itoc write
+    mem 10 + over 28 >> 15 & itoc write
+    mem 11 + over 24 >> 15 & itoc write
+    mem 12 + over 20 >> 15 & itoc write
+    mem 13 + over 16 >> 15 & itoc write
+    mem 14 + over 12 >> 15 & itoc write
+    mem 15 + over 8 >> 15 & itoc write
+    mem 16 + over 4 >> 15 & itoc write
+    mem 17 + over 0 >> 15 & itoc write
+    mem println
+    drop
+marine
+
+[Converts an integer between 0-15 to the ASCII hex character]
+[arg:int number to convert]
+[ret:int ascii character]
+sub itoc
+    swap clone 10 < if 48 +
+    else 55 + endif swap
+marine
+

std/sys/mem.alc

@@ -0,0 +1,125 @@
+include std.sys.call
+include std.io
+include std.math
+
+sub BLOCK_FREE 0 swap marine
+sub BLOCK_USED 1 swap marine
+sub PAGE_SIZE_BYTES 4096 swap marine
+sub BLOCK_HEADER_SIZE 8 swap marine
+
+[Modifies the end address of the heap]
+[arg:int New address in number of bytes]
+[ret:ptr End address of heap]
+sub brk
+    swap 12 syscall1 sysread swap
+marine
+
+[Read the current end of the heap]
+[ret:ptr End address of heap]
+sub heap_end
+    0 brk swap
+marine
+
+[Increases the heap by a set amount of bytes.]
+[arg:int number of bytes]
+[ret:void]
+sub incheap
+    swap heap_end + brk
+    0 < if
+        "Unable to increase heap memory" println
+        1 SYS_EXIT syscall1
+    endif
+marine
+
+[Initializes the memory allocator]
+[ret:void]
+sub mem_init
+    "Initializing heap allocator @ " print 0 brk printx
+    [Allocate first block (empty)]
+    [Dont allocate 0 bytes or this will break :)]
+    BLOCK_HEADER_SIZE incheap
+    heap_end BLOCK_HEADER_SIZE + BLOCK_FREE write
+
+    10000 incheap [Starting memory]
+    heap_end BLOCK_HEADER_SIZE -
+    BLOCK_FREE 10000 + BLOCK_HEADER_SIZE - BLOCK_HEADER_SIZE - write
+marine
+
+[Coalesces adjacent free memory blocks]
+[ret:void]
+sub mem_coalesce
+marine
+
+
+[Allocates bytes on the heap]
+[arg:int number of bytes to allocate]
+[ret:ptr address of allocated block]
+sub malloc
+    swap
+    heap_end BLOCK_HEADER_SIZE -
+    while 1 do
+        clone load 1 & BLOCK_FREE = if
+            [This block is free]
+            2clone load < if
+                [This block is large enough]
+                clone load 18446744073709551614 & rev3 swap
+                2clone swap BLOCK_USED + write
+                [Address magic]
+                swap clone rev3 swap - rev3 swap clone rev3 swap - swap rev3 swap over swap write
+                clone rev3 swap
+                clone
+                "New allocation:" println
+                "  Header Address: " print printx
+                "  Size:           " print printx
+                + swap
+                return
+            else
+                [This block is too small]
+                clone load 18446744073709551614 &
+                clone 0 = if
+                    "FATALERR Found last memory block. Not enough memory." println
+                    1 SYS_EXIT syscall1
+                endif
+                - 
+            endif
+        else
+            [This block is used]
+            clone load 18446744073709551614 &
+            clone 0 = if
+                "FATALERR Found last memory block. Not enough memory." println
+                1 SYS_EXIT syscall1
+            endif
+            - 
+        endif
+    wend
+    [Should return early or exit with not enough memory]
+marine
+
+[Deallocates a memory block on the heap]
+[arg:ptr address of block header]
+sub free
+    swap clone clone load 18446744073709551614 & write drop
+marine
+
+sub mem_walk
+    "Starting memory walk at heap end: " print heap_end printx
+    heap_end BLOCK_HEADER_SIZE -
+    while 1 do
+        "Block: " print clone printx
+        clone load
+        "   Free:  " print
+        clone 1 & BLOCK_FREE = if
+            "Yes" println
+        else
+            "No" println
+        endif
+        "   Size:  " print clone 18446744073709551614 & printx
+        clone 18446744073709551614 & 0 = if
+            drop
+            drop
+            return
+        endif
+        "   Next:  " print 18446744073709551614 & - clone printx
+    wend
+    "==========" println
+marine