68 lines
1.3 KiB
C++
68 lines
1.3 KiB
C++
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#define WASM_PAGE_SIZE KB(64)
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u64
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platform_page_size()
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{
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return WASM_PAGE_SIZE;
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}
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// this comes from: https://surma.dev/things/c-to-webassembly/
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extern u8 __heap_base;
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global u8* heap_base = &__heap_base;
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global u64 heap_used = 0;
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WASM_EXTERN u32 wasm_get_memory_size();
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WASM_EXTERN u32 wasm_mem_grow(u32 new_size);
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u64
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wasm_get_heap_size()
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{
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u64 memory_size = wasm_get_memory_size();
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u64 heap_base_addr = (u64)&__heap_base;
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u64 heap_size = memory_size - heap_base_addr;
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return heap_size;
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}
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u8*
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platform_mem_reserve(u64 size)
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{
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// if we are out of memory, double the size of wasm memory
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u64 heap_size = wasm_get_heap_size();
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if (heap_used + size >= heap_size)
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{
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u32 heap_size_new = heap_size * 2;
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if (heap_used + size >= heap_size_new)
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{
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heap_size_new = heap_used + size;
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}
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wasm_mem_grow(heap_size_new);
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}
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assert(heap_used + size <= wasm_get_heap_size());
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u64 ptr_addr = (u64)(heap_base + heap_used);
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u8* result = heap_base + heap_used;
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heap_used += size; // TODO(PS): alignment
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return result;
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}
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u8*
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platform_mem_commit(u8* base, u64 size)
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{
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return base;
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}
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bool
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platform_mem_decommit(u8* base, u64 size)
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{
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return true;
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}
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bool
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platform_mem_release(u8* base, u64 size)
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{
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// TODO(PS): we probably actually want to implement free at some point
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return true;
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}
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