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* 6173Kartik Agaram2020-03-271-5/+12
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* 6170Kartik Agaram2020-03-251-3/+3
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* 6169Kartik Agaram2020-03-251-1/+1
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* 6164Kartik Agaram2020-03-241-2/+2
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* 6160 - plan for safe heap accessKartik Agaram2020-03-211-2/+31
| | | | | | | | | Based on apps/handle.subx (commit 4894), but we're able to simplify it further now that we know more about the situation we find ourselves in. 6 instructions, zero pushes or pops. Before I can start building this, I need to reorganize my use of handles. They're going to be fat pointers so we can't store them in registers anymore.
* 6159Kartik Agaram2020-03-211-218/+165
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* 6158 - standardize opcode namesKartik Agaram2020-03-211-29/+29
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | At the lowest level, SubX without syntax sugar uses names without prepositions. For example, 01 and 03 are both called 'add', irrespective of source and destination operand. Horizontal space is at a premium, and we rely on the comments at the end of each line to fully describe what is happening. Above that, however, we standardize on a slightly different naming convention across: a) SubX with syntax sugar, b) Mu, and c) the SubX code that the Mu compiler emits. Conventions, in brief: - by default, the source is on the left and destination on the right. e.g. add %eax, 1/r32/ecx ("add eax to ecx") - prepositions reverse the direction. e.g. add-to %eax, 1/r32/ecx ("add ecx to eax") subtract-from %eax, 1/r32/ecx ("subtract ecx from eax") - by default, comparisons are left to right while 'compare<-' reverses. Before, I was sometimes swapping args to make the operation more obvious, but that would complicate the code-generation of the Mu compiler, and it's nice to be able to read the output of the compiler just like hand-written code. One place where SubX differs from Mu: copy opcodes are called '<-' and '->'. Hopefully that fits with the spirit of Mu rather than the letter of the 'copy' and 'copy-to' instructions.
* 6145 - 'address' operatorKartik Agaram2020-03-141-0/+5
| | | | | This could be a can of worms, but I think I have a set of checks that will keep use of addresses type-safe.
* 6131 - operating on arrays on the stackKartik Agaram2020-03-121-1/+5
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* 6129Kartik Agaram2020-03-111-1/+3
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* 6097Kartik Agaram2020-03-071-2/+0
| | | | | | I thought I needed to support compute-offset with literal index, but in that case might as well just use an index literal directly. The 'index' instruction with literals already supports non-power-of-2 sizes.
* 6094 - new 'compute-offset' instructionKartik Agaram2020-03-071-3/+11
| | | | | | | | | | | | | | | | | | | | | | | If indexing into a type with power-of-2-sized elements we can access them in one instruction: x/reg1: (addr int) <- index A/reg2: (addr array int), idx/reg3: int This translates to a single instruction because x86 instructions support an addressing mode with left-shifts. For non-powers-of-2, however, we need a multiply. To keep things type-safe, it is performed like this: x/reg1: (offset T) <- compute-offset A: (addr array T), idx: int y/reg2: (addr T) <- index A, x An offset is just an int that is guaranteed to be a multiple of size-of(T). Offsets can only be used in index instructions, and the types will eventually be required to line up. In the process, I have to expand Input-size because mu.subx is growing big.
* 6060Kartik Agaram2020-02-271-11/+11
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* 6059Kartik Agaram2020-02-271-0/+8
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* 6041 - array indexing starting to workKartik Agaram2020-02-211-0/+10
| | | | | | | | | | | | | And we're using it now in factorial.mu! In the process I had to fix a couple of bugs in pointer dereferencing. There are still some limitations: a) Indexing by a literal doesn't work yet. b) Only arrays of ints supported so far. Looking ahead, I'm not sure how I can support indexing arrays by non-literals (variables in registers) unless the element size is a power of 2.
* 6039Kartik Agaram2020-02-211-0/+18
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* 6019 - finish supporting all branch primitivesKartik Agaram2020-02-181-2/+2
| | | | | | | | I'd been thinking I didn't need unconditional `break` instructions, but I just realized that non-local unconditional breaks have a use. Stop over-thinking this, just support everything. The code is quite duplicated.
* 5968Kartik Agaram2020-02-011-24/+22
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* 5967Kartik Agaram2020-02-011-0/+6
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* 5966 - document all supported Mu instructionsKartik Agaram2020-01-311-0/+186