diff options
| -rw-r--r-- | subx/010---vm.cc | 22 |
1 files changed, 14 insertions, 8 deletions
diff --git a/subx/010---vm.cc b/subx/010---vm.cc index a71d431f..24051ec4 100644 --- a/subx/010---vm.cc +++ b/subx/010---vm.cc @@ -122,12 +122,8 @@ struct vma { uint32_t start; // inclusive uint32_t end; // exclusive vector<uint8_t> _data; - vma(uint32_t s, uint32_t e) :start(s), end(e) { - _data.resize(end-start); - } - vma(uint32_t s) :start(s), end(s+INITIAL_SEGMENT_SIZE) { - _data.resize(end-start); - } + vma(uint32_t s, uint32_t e) :start(s), end(e) {} + vma(uint32_t s) :start(s), end(s+INITIAL_SEGMENT_SIZE) {} bool match(uint32_t a) { return a >= start && a < end; } @@ -136,7 +132,18 @@ struct vma { } uint8_t& data(uint32_t a) { assert(match(a)); - return _data.at(a-start); + uint32_t result_index = a-start; + if (_data.size() <= result_index) { + const int align = 0x1000; + uint32_t result_size = result_index + 1; // size needed for result_index to be valid + #define align_upwards(x, align) (((x)+(align)-1) & -(align)) + uint32_t new_size = align_upwards(result_size, align); + #undef align_upwards + if (new_size > end-start) + new_size = end-start; + _data.resize(new_size); + } + return _data.at(result_index); } void grow_until(uint32_t new_end_address) { if (new_end_address < end) return; @@ -144,7 +151,6 @@ struct vma { void sanity_check(uint32_t start, uint32_t end); sanity_check(start, new_end_address); end = new_end_address; - _data.resize(new_end_address - start); } // End vma Methods }; |