diff options
| -rw-r--r-- | subx/012elf.cc | 16 | ||||
| -rw-r--r-- | subx/037heap.cc | 29 | ||||
| -rw-r--r-- | subx/038---literal_strings.cc | 7 | ||||
| -rw-r--r-- | subx/053new-segment.subx | 13 | ||||
| -rw-r--r-- | subx/069allocate.subx | 8 |
5 files changed, 26 insertions, 47 deletions
diff --git a/subx/012elf.cc b/subx/012elf.cc index 0f058504..6a31826e 100644 --- a/subx/012elf.cc +++ b/subx/012elf.cc @@ -129,15 +129,13 @@ void load_segment_from_program_header(uint8_t* elf_contents, int segment_index, } :(before "End Includes") -// Very primitive/fixed/insecure ELF segments for now: just consecutive VMAs. -// code: 0x09000000 -> 0x09ffffff -// data/heap: 0x0a000000 -> 0x0affffff -// stack: 0x0b000ffc -> 0x0b000000 (downward) -const int CODE_SEGMENT = 0x09000000; -const int DATA_SEGMENT = 0x0a000000; // keep sync'd with `Heap.limit` in allocate.subx -const int STACK_SEGMENT = 0x0b000000; -const int AFTER_STACK = 0x0c000000; -const int ARGV_DATA_SEGMENT = 0x0c000000; +// Very primitive/fixed/insecure ELF segments for now. +// code: 0x09000000 -> 0x09ffffff +// stack: 0xbe000000 -> 0xb0000000 (downward) +const int CODE_SEGMENT = 0x09000000; +const int STACK_SEGMENT = 0xb0000000; +const int AFTER_STACK = 0xbe000000; +const int ARGV_DATA_SEGMENT = 0xbf000000; :(before "End Dump Info for Instruction") //? dump_stack(); // slow :(code) diff --git a/subx/037heap.cc b/subx/037heap.cc deleted file mode 100644 index 315fd0d5..00000000 --- a/subx/037heap.cc +++ /dev/null @@ -1,29 +0,0 @@ -//: Support for dynamic allocation. -//: -//: Just provide a special label marking the first unused address in the data -//: segment. Then we'll write SubX helpers to make use of it. - -:(before "Begin rewrite_global_variables") -insert_heap_global_variable(p); -:(code) -void insert_heap_global_variable(program& p) { - if (SIZE(p.segments) < 2) - return; // no data segment defined - // Start-of-heap: - p.segments.at(1).lines.push_back(label("Start-of-heap")); -} - -line label(string s) { - line result; - result.words.push_back(word()); - result.words.back().data = (s+":"); - return result; -} - -line imm32(const string& s) { - line result; - result.words.push_back(word()); - result.words.back().data = s; - result.words.back().metadata.push_back("imm32"); - return result; -} diff --git a/subx/038---literal_strings.cc b/subx/038---literal_strings.cc index 65a7740b..9b2c3902 100644 --- a/subx/038---literal_strings.cc +++ b/subx/038---literal_strings.cc @@ -184,6 +184,13 @@ void skip_comment(istream& in) { } } +line label(string s) { + line result; + result.words.push_back(word()); + result.words.back().data = (s+":"); + return result; +} + // helper for tests void parse_instruction_character_by_character(const string& line_data) { vector<line> out; diff --git a/subx/053new-segment.subx b/subx/053new-segment.subx index 1669b097..21837628 100644 --- a/subx/053new-segment.subx +++ b/subx/053new-segment.subx @@ -1,4 +1,15 @@ -# Create a new segment (for data) using mmap(). +# Create a new segment (pool of memory for allocating chunks from) in the form +# of an *allocation descriptor* that can be passed to the memory allocator +# (defined in a later layer). +# +# Currently an allocation descriptor consists of just the bounds of the pool of +# available memory: +# +# curr : address +# end : address +# +# This isn't enough information to reclaim individual allocations. We can't +# support arbitrary reclamation yet. == code # instruction effective address register displacement immediate diff --git a/subx/069allocate.subx b/subx/069allocate.subx index 402467fe..14e9fd50 100644 --- a/subx/069allocate.subx +++ b/subx/069allocate.subx @@ -16,14 +16,6 @@ # very same 'allocate' helper. They just need a new allocation descriptor for # their book-keeping. -== data - -# The 'global' allocation descriptor. Pass this into 'allocate' to claim a -# hitherto unused bit of memory. -Heap: - Start-of-heap/imm32 # curr - 0x0b000000/imm32 # limit; keep sync'd with DATA_SEGMENT + SEGMENT_ALIGNMENT - == code # instruction effective address register displacement immediate # . op subop mod rm32 base index scale r32 |