const ALIGN_LOG2: usize = 3;
const ALIGN_SIZE: usize = 1 << ALIGN_LOG2;
const ALIGN_MASK: usize = ALIGN_SIZE - 1;
let HEAP_OFFSET: usize = HEAP_BASE; // HEAP_BASE is a constant generated by the compiler
// TODO: maybe tlsf
@global()
export class Heap {
static get used(): usize { return HEAP_OFFSET - HEAP_BASE; }
static get free(): usize { return (<usize>current_memory() << 16) - HEAP_OFFSET; }
static get size(): usize { return (<usize>current_memory() << 16) - HEAP_BASE; }
static allocate(size: usize): usize {
if (!size) return 0;
const len: i32 = current_memory();
if (HEAP_OFFSET + size > <usize>len << 16)
if(grow_memory(max<i32>(<i32>ceil<f64>(<f64>size / 65536), len * 2 - len)) < 0)
unreachable();
const ptr: usize = HEAP_OFFSET;
if ((HEAP_OFFSET += size) & ALIGN_MASK) // align next offset
HEAP_OFFSET = (HEAP_OFFSET | ALIGN_MASK) + 1;
return ptr;
}
static dispose(ptr: usize): void {
// just a big chunk of non-disposable memory for now
}
static copy(dest: usize, src: usize, n: usize): usize { // TODO: use move_memory op once available
assert(dest >= HEAP_BASE);
// the following is based on musl's implementation of memcpy
let dst: usize = dest;
let w: u32, x: u32;
// copy 1 byte each until src is aligned to 4 bytes
while (n && src % 4) {
store<u8>(dst++, load<u8>(src++));
n--;
}
// if dst is aligned to 4 bytes as well, copy 4 bytes each
if (dst % 4 == 0) {
while (n >= 16) {
store<u32>(dst , load<u32>(src ));
store<u32>(dst + 4, load<u32>(src + 4));
store<u32>(dst + 8, load<u32>(src + 8));
store<u32>(dst + 12, load<u32>(src + 12));
src += 16; dst += 16; n -= 16;
}
if (n & 8) {
store<u32>(dst , load<u32>(src ));
store<u32>(dst + 4, load<u32>(src + 4));
dst += 8; src += 8;
}
if (n & 4) {
store<u32>(dst, load<u32>(src));
dst += 4; src += 4;
}
if (n & 2) { // drop to 2 bytes each
store<u16>(dst, load<u16>(src));
dst += 2; src += 2;
}
if (n & 1) { // drop to 1 byte
store<u8>(dst++, load<u8>(src++));
}
return dest;
}
// if dst is not aligned to 4 bytes, use alternating shifts to copy 4 bytes each
// doing shifts if faster when copying enough bytes (here: 32 or more)
if (n >= 32) {
switch (dst % 4) {
// known to be != 0
case 1:
w = load<u32>(src);
store<u8>(dst++, load<u8>(src++));
store<u8>(dst++, load<u8>(src++));
store<u8>(dst++, load<u8>(src++));
n -= 3;
while (n >= 17) {
x = load<u32>(src + 1);
store<u32>(dst, w >> 24 | x << 8);
w = load<u32>(src + 5);
store<u32>(dst + 4, x >> 24 | w << 8);
x = load<u32>(src + 9);
store<u32>(dst + 8, w >> 24 | x << 8);
w = load<u32>(src + 13);
store<u32>(dst + 12, x >> 24 | w << 8);
src += 16; dst += 16; n -= 16;
}
break;
case 2:
w = load<u32>(src);
store<u8>(dst++, load<u8>(src++));
store<u8>(dst++, load<u8>(src++));
n -= 2;
while (n >= 18) {
x = load<u32>(src + 2);
store<u32>(dst, w >> 16 | x << 16);
w = load<u32>(src + 6);
store<u32>(dst + 4, x >> 16 | w << 16);
x = load<u32>(src + 10);
store<u32>(dst + 8, w >> 16 | x << 16);
w = load<u32>(src + 14);
store<u32>(dst + 12, x >> 16 | w << 16);
src += 16; dst += 16; n -= 16;
}
break;
case 3:
w = load<u32>(src);
store<u8>(dst++, load<u8>(src++));
n -= 1;
while (n >= 19) {
x = load<u32>(src + 3);
store<u32>(dst, w >> 8 | x << 24);
w = load<u32>(src + 7);
store<u32>(dst + 4, x >> 8 | w << 24);
x = load<u32>(src + 11);
store<u32>(dst + 8, w >> 8 | x << 24);
w = load<u32>(src + 15);
store<u32>(dst + 12, x >> 8 | w << 24);
src += 16; dst += 16; n -= 16;
}
break;
}
}
// copy remaining bytes one by one
if (n & 16) {
store<u8>(dst++, load<u8>(src++));
store<u8>(dst++, load<u8>(src++));
store<u8>(dst++, load<u8>(src++));
store<u8>(dst++, load<u8>(src++));
store<u8>(dst++, load<u8>(src++));
store<u8>(dst++, load<u8>(src++));
store<u8>(dst++, load<u8>(src++));
store<u8>(dst++, load<u8>(src++));
store<u8>(dst++, load<u8>(src++));
store<u8>(dst++, load<u8>(src++));
store<u8>(dst++, load<u8>(src++));
store<u8>(dst++, load<u8>(src++));
store<u8>(dst++, load<u8>(src++));
store<u8>(dst++, load<u8>(src++));
store<u8>(dst++, load<u8>(src++));
store<u8>(dst++, load<u8>(src++));
}
if (n & 8) {
store<u8>(dst++, load<u8>(src++));
store<u8>(dst++, load<u8>(src++));
store<u8>(dst++, load<u8>(src++));
store<u8>(dst++, load<u8>(src++));
store<u8>(dst++, load<u8>(src++));
store<u8>(dst++, load<u8>(src++));
store<u8>(dst++, load<u8>(src++));
store<u8>(dst++, load<u8>(src++));
}
if (n & 4) {
store<u8>(dst++, load<u8>(src++));
store<u8>(dst++, load<u8>(src++));
store<u8>(dst++, load<u8>(src++));
store<u8>(dst++, load<u8>(src++));
}
if (n & 2) {
store<u8>(dst++, load<u8>(src++));
store<u8>(dst++, load<u8>(src++));
}
if (n & 1) {
store<u8>(dst++, load<u8>(src++));
}
return dest;
}
static fill(dest: usize, c: u8, n: usize): usize { // TODO: use set_memory op once available
assert(dest >= HEAP_BASE);
// the following is based on musl's implementation of memset
if (!n) return dest;
let s: usize = dest;
// Fill head and tail with minimal branching
store<u8>(s, c); store<u8>(s + n - 1, c);
if (n <= 2) return dest;
store<u8>(s + 1, c); store<u8>(s + n - 2, c);
store<u8>(s + 2, c); store<u8>(s + n - 3, c);
if (n <= 6) return dest;
store<u8>(s + 3, c); store<u8>(s + n - 4, c);
if (n <= 8) return dest;
// Align to 4 bytes
let k: usize = -s & 3;
s += k;
n -= k;
n &= -4;
let c32: u32 = -1 / 255 * c;
// Fill head and tail in preparation of setting 32 bytes at a time
store<u32>(s, c32);
store<u32>(s + n - 4, c32);
if (n <= 8) return dest;
store<u32>(s + 4, c32);
store<u32>(s + 8, c32);
store<u32>(s + n - 12, c32);
store<u32>(s + n - 8, c32);
if (n <= 24) return dest;
store<u32>(s + 12, c32);
store<u32>(s + 16, c32);
store<u32>(s + 20, c32);
store<u32>(s + 24, c32);
store<u32>(s + n - 28, c32);
store<u32>(s + n - 24, c32);
store<u32>(s + n - 20, c32);
store<u32>(s + n - 16, c32);
// Align to 8 bytes
k = 24 + (s & 4);
s += k;
n -= k;
// Set 32 bytes at a time
let c64: u64 = <u64>c32 | (<u64>c32 << 32);
while (n >= 32) {
store<u64>(s, c64);
store<u64>(s + 8, c64);
store<u64>(s + 16, c64);
store<u64>(s + 24, c64);
n -= 32; s += 32;
}
return dest;
}
static compare(vl: usize, vr: usize, n: usize): i32 {
if (vl == vr) return 0;
// the following is based on musl's implementation of memcmp
while (n && load<u8>(vl) == load<u8>(vr)) {
n--; vl++; vr++;
}
return n ? <i32>load<u8>(vl) - <i32>load<u8>(vr) : 0;
}
private constructor() {}
}