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38 lines
1.6 KiB
Markdown
38 lines
1.6 KiB
Markdown
# Assembly
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Assembly tokenization should be working completely. It knows what instructions the CPU implementation supports and parses based on them.
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## Instruction sets:
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* RV32I
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* Loads/Stores: `lb, lh, lw, lbu, lhu, sw, sh, sb` (supported arg format is either `rd, imm(reg)` or `rd, reg, imm`)
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* Branch statements: `beq, bne, blt, bge, bltu, bgeu`
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* Jumps `j, jal, jalr, ret`
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* Basic arithmetic: `add, addi, sub, lui, auipc`
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* Shifts: `sll, slli, srl, srli, sra, srai`
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* Syscall/Debugging:`scall, ecall, sbreak, ebreak` (both `s` and `e` version are the same instruction)
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* Compares: `slt, sltu, slti, sltiu`
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* Logical: `and, or, xor, andi, ori, xori`
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* Not implemented: `fence, fence.i, rdcycle, rdcycleh, rdtime, rdtimeh, rdinstret, rdinstreth`
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* RV32M
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* Multiplication: `mul, mulh`, not implemented yet are `mulhsu, mulhu`
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* Division: `div, divu, rem, remu`
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## Pseudo-ops
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The following pseudo-ops are implemented as of yet:
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* `.space <len>` reverse <len> bytes of zero
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* `.ascii 'text'` put text into memory
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* `.asciiz 'text'` put text into memory (null terminated)
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* `.section .<name>` same as `.<name>`, see sections
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* `.set <name>, <value>` to create a const symbol with a given value
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* `.global <name>` mark symbol `<name>` as a global symbol. It is available from all loaded programs
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* `.align <bytes>` currently a nop as cpu does not care about alignment as of now
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## Sections:
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Currently only these three sections are supported:
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* `data` read-write data (non-executable)
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* `rodata` read-only data (non-executable)
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* `text` executable data (read-only)
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