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assemblyscript/std/assembly/heap.ts
dcodeIO f2ba4b4a76 Filler implementation for std Set
2018-01-15 00:08:06 +01:00

293 lines
8.0 KiB
TypeScript
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const ALIGN_LOG2: usize = 3;
const ALIGN_SIZE: usize = 1 << ALIGN_LOG2;
const ALIGN_MASK: usize = ALIGN_SIZE - 1;
var HEAP_OFFSET: usize = HEAP_BASE; // HEAP_BASE is a constant generated by the compiler
export function allocate_memory(size: usize): usize {
if (!size) return 0;
var 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();
var ptr: usize = HEAP_OFFSET;
if ((HEAP_OFFSET += size) & ALIGN_MASK) // align next offset
HEAP_OFFSET = (HEAP_OFFSET | ALIGN_MASK) + 1;
return ptr;
}
export function free_memory(ptr: usize): void {
// just a big chunk of non-disposable memory for now
}
function copy_memory(dest: usize, src: usize, n: usize): void {
// based on musl's implementation of memcpy
// not a future instruction and sufficiently covered by the upcoming move_memory intrinsic
var w: u32, x: u32;
// copy 1 byte each until src is aligned to 4 bytes
while (n && src % 4) {
store<u8>(dest++, load<u8>(src++));
n--;
}
// if dst is aligned to 4 bytes as well, copy 4 bytes each
if (dest % 4 == 0) {
while (n >= 16) {
store<u32>(dest , load<u32>(src ));
store<u32>(dest + 4, load<u32>(src + 4));
store<u32>(dest + 8, load<u32>(src + 8));
store<u32>(dest + 12, load<u32>(src + 12));
src += 16; dest += 16; n -= 16;
}
if (n & 8) {
store<u32>(dest , load<u32>(src ));
store<u32>(dest + 4, load<u32>(src + 4));
dest += 8; src += 8;
}
if (n & 4) {
store<u32>(dest, load<u32>(src));
dest += 4; src += 4;
}
if (n & 2) { // drop to 2 bytes each
store<u16>(dest, load<u16>(src));
dest += 2; src += 2;
}
if (n & 1) { // drop to 1 byte
store<u8>(dest++, load<u8>(src++));
}
return;
}
// 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 (dest % 4) {
// known to be != 0
case 1:
w = load<u32>(src);
store<u8>(dest++, load<u8>(src++));
store<u8>(dest++, load<u8>(src++));
store<u8>(dest++, load<u8>(src++));
n -= 3;
while (n >= 17) {
x = load<u32>(src + 1);
store<u32>(dest, w >> 24 | x << 8);
w = load<u32>(src + 5);
store<u32>(dest + 4, x >> 24 | w << 8);
x = load<u32>(src + 9);
store<u32>(dest + 8, w >> 24 | x << 8);
w = load<u32>(src + 13);
store<u32>(dest + 12, x >> 24 | w << 8);
src += 16; dest += 16; n -= 16;
}
break;
case 2:
w = load<u32>(src);
store<u8>(dest++, load<u8>(src++));
store<u8>(dest++, load<u8>(src++));
n -= 2;
while (n >= 18) {
x = load<u32>(src + 2);
store<u32>(dest, w >> 16 | x << 16);
w = load<u32>(src + 6);
store<u32>(dest + 4, x >> 16 | w << 16);
x = load<u32>(src + 10);
store<u32>(dest + 8, w >> 16 | x << 16);
w = load<u32>(src + 14);
store<u32>(dest + 12, x >> 16 | w << 16);
src += 16; dest += 16; n -= 16;
}
break;
case 3:
w = load<u32>(src);
store<u8>(dest++, load<u8>(src++));
n -= 1;
while (n >= 19) {
x = load<u32>(src + 3);
store<u32>(dest, w >> 8 | x << 24);
w = load<u32>(src + 7);
store<u32>(dest + 4, x >> 8 | w << 24);
x = load<u32>(src + 11);
store<u32>(dest + 8, w >> 8 | x << 24);
w = load<u32>(src + 15);
store<u32>(dest + 12, x >> 8 | w << 24);
src += 16; dest += 16; n -= 16;
}
break;
}
}
// copy remaining bytes one by one
if (n & 16) {
store<u8>(dest++, load<u8>(src++));
store<u8>(dest++, load<u8>(src++));
store<u8>(dest++, load<u8>(src++));
store<u8>(dest++, load<u8>(src++));
store<u8>(dest++, load<u8>(src++));
store<u8>(dest++, load<u8>(src++));
store<u8>(dest++, load<u8>(src++));
store<u8>(dest++, load<u8>(src++));
store<u8>(dest++, load<u8>(src++));
store<u8>(dest++, load<u8>(src++));
store<u8>(dest++, load<u8>(src++));
store<u8>(dest++, load<u8>(src++));
store<u8>(dest++, load<u8>(src++));
store<u8>(dest++, load<u8>(src++));
store<u8>(dest++, load<u8>(src++));
store<u8>(dest++, load<u8>(src++));
}
if (n & 8) {
store<u8>(dest++, load<u8>(src++));
store<u8>(dest++, load<u8>(src++));
store<u8>(dest++, load<u8>(src++));
store<u8>(dest++, load<u8>(src++));
store<u8>(dest++, load<u8>(src++));
store<u8>(dest++, load<u8>(src++));
store<u8>(dest++, load<u8>(src++));
store<u8>(dest++, load<u8>(src++));
}
if (n & 4) {
store<u8>(dest++, load<u8>(src++));
store<u8>(dest++, load<u8>(src++));
store<u8>(dest++, load<u8>(src++));
store<u8>(dest++, load<u8>(src++));
}
if (n & 2) {
store<u8>(dest++, load<u8>(src++));
store<u8>(dest++, load<u8>(src++));
}
if (n & 1) {
store<u8>(dest++, load<u8>(src++));
}
}
export function move_memory(dest: usize, src: usize, n: usize): void {
// based on musl's implementation of memmove
// becomes obsolete once https://github.com/WebAssembly/bulk-memory-operations lands
if (dest == src)
return;
if (src + n <= dest || dest + n <= src) {
copy_memory(dest, src, n);
return;
}
if (dest < src) {
if (src % 8 == dest % 8) {
while (dest % 8) {
if (!n)
return;
--n;
store<u8>(dest++, load<u8>(src++));
}
while (n >= 8) {
store<u64>(dest, load<u64>(src));
n -= 8;
dest += 8;
src += 8;
}
}
while (n) {
store<u8>(dest++, load<u8>(src++));
--n;
}
} else {
if (src % 8 == dest % 8) {
while ((dest + n) % 8) {
if (!n)
return;
store<u8>(dest + --n, load<u8>(src + n));
}
while (n >= 8) {
n -= 8;
store<u64>(dest + n, load<u64>(src + n));
}
}
while (n) {
store<u8>(dest + --n, load<u8>(src + n));
}
}
}
export function set_memory(dest: usize, c: u8, n: usize): void {
// based on musl's implementation of memset
// becomes obsolete once https://github.com/WebAssembly/bulk-memory-operations lands
// fill head and tail with minimal branching
if (!n)
return;
store<u8>(dest, c);
store<u8>(dest + n - 1, c);
if (n <= 2)
return;
store<u8>(dest + 1, c);
store<u8>(dest + 2, c);
store<u8>(dest + n - 2, c);
store<u8>(dest + n - 3, c);
if (n <= 6)
return;
store<u8>(dest + 3, c);
store<u8>(dest + n - 4, c);
if (n <= 8)
return;
// advance pointer to align it at 4-byte boundary
var k: usize = -dest & 3;
dest += k;
n -= k;
n &= -4;
var c32: u32 = -1 / 255 * c;
// fill head/tail up to 28 bytes each in preparation
store<u32>(dest, c32);
store<u32>(dest + n - 4, c32);
if (n <= 8)
return;
store<u32>(dest + 4, c32);
store<u32>(dest + 8, c32);
store<u32>(dest + n - 12, c32);
store<u32>(dest + n - 8, c32);
if (n <= 24)
return;
store<u32>(dest + 12, c32);
store<u32>(dest + 16, c32);
store<u32>(dest + 20, c32);
store<u32>(dest + 24, c32);
store<u32>(dest + n - 28, c32);
store<u32>(dest + n - 24, c32);
store<u32>(dest + n - 20, c32);
store<u32>(dest + n - 16, c32);
// align to a multiple of 8
k = 24 + (dest & 4);
dest += k;
n -= k;
// copy 32 bytes each
var c64: u64 = <u64>c32 | (<u64>c32 << 32);
while (n >= 32) {
store<u64>(dest, c64);
store<u64>(dest + 8, c64);
store<u64>(dest + 16, c64);
store<u64>(dest + 24, c64);
n -= 32;
dest += 32;
}
}
export function compare_memory(vl: usize, vr: usize, n: usize): i32 {
// based on musl's implementation of memcmp
// provided because there's no proposed alternative
if (vl == vr)
return 0;
while (n && load<u8>(vl) == load<u8>(vr)) {
n--;
vl++;
vr++;
}
return n ? <i32>load<u8>(vl) - <i32>load<u8>(vr) : 0;
}
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