122 lines
5.5 KiB
Plaintext
122 lines
5.5 KiB
Plaintext
# write-int: add (the binary representation of) a single int to a stream
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== code
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# instruction effective address register displacement immediate
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# . op subop mod rm32 base index scale r32
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# . 1-3 bytes 3 bits 2 bits 3 bits 3 bits 3 bits 2 bits 2 bits 0/1/2/4 bytes 0/1/2/4 bytes
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write-int: # out: (addr stream byte), n: int
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# . prologue
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55/push-ebp
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89/copy 3/mod/direct 5/rm32/ebp . . . 4/r32/esp . . # copy esp to ebp
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# . save registers
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50/push-eax
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51/push-ecx
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57/push-edi
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# edi = out
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8b/copy 1/mod/*+disp8 5/rm32/ebp . . . 7/r32/edi 8/disp8 . # copy *(ebp+8) to edi
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# ecx = out->write
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8b/copy 0/mod/indirect 7/rm32/edi . . . 1/r32/ecx . . # copy *edi to ecx
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# if (out->write >= out->size) abort
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3b/compare 1/mod/*+disp8 7/rm32/edi . . . 1/r32/ecx 8/disp8 . # compare ecx with *(edi+8)
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7d/jump-if->= $write-int:abort/disp8
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$write-int:to-stream:
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# out->data[out->write] = n
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8b/copy 1/mod/*+disp8 5/rm32/ebp . . . 0/r32/eax 0xc/disp8 . # copy *(ebp+12) to eax
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89/copy 1/mod/*+disp8 4/rm32/sib 7/base/edi 1/index/ecx . 0/r32/eax 0xc/disp8 . # copy eax to *(edi+ecx+12)
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# out->write += 4
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81 0/subop/add 0/mod/indirect 7/rm32/edi . . . . . 4/imm32 # add to *edi
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$write-int:end:
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# . restore registers
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5f/pop-to-edi
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59/pop-to-ecx
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58/pop-to-eax
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# . epilogue
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89/copy 3/mod/direct 4/rm32/esp . . . 5/r32/ebp . . # copy ebp to esp
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5d/pop-to-ebp
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c3/return
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$write-int:abort:
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# . _write(2/stderr, error)
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# . . push args
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68/push "write-int: out of space\n"/imm32
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68/push 2/imm32/stderr
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# . . call
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e8/call _write/disp32
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# . . discard args
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81 0/subop/add 3/mod/direct 4/rm32/esp . . . . . 8/imm32 # add to esp
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# . syscall_exit(1)
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bb/copy-to-ebx 1/imm32
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e8/call syscall_exit/disp32
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# never gets here
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test-write-int-single:
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# - check that write-int writes to first int of 'stream'
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# setup
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# . clear-stream(_test-stream)
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# . . push args
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68/push _test-stream/imm32
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# . . call
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e8/call clear-stream/disp32
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# . . discard args
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81 0/subop/add 3/mod/direct 4/rm32/esp . . . . . 4/imm32 # add to esp
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# write-int(_test-stream, "abcd")
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# . . push args
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68/push 0x64636261/imm32
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68/push _test-stream/imm32
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# . . call
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e8/call write-int/disp32
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# . . discard args
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81 0/subop/add 3/mod/direct 4/rm32/esp . . . . . 8/imm32 # add to esp
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# check-stream-equal(_test-stream, "abcd", msg)
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# . . push args
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68/push "F - test-write-int-single"/imm32
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68/push "abcd"/imm32
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68/push _test-stream/imm32
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# . . call
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e8/call check-stream-equal/disp32
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# . . discard args
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81 0/subop/add 3/mod/direct 4/rm32/esp . . . . . 0xc/imm32 # add to esp
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# . end
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c3/return
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test-write-byte-buffered-multiple:
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# - check that write-int correctly appends multiple writes
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# setup
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# . clear-stream(_test-stream)
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# . . push args
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68/push _test-stream/imm32
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# . . call
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e8/call clear-stream/disp32
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# . . discard args
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81 0/subop/add 3/mod/direct 4/rm32/esp . . . . . 4/imm32 # add to esp
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# write-int(_test-stream, "abcd")
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# . . push args
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68/push 0x64636261/imm32
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68/push _test-stream/imm32
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# . . call
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e8/call write-int/disp32
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# . . discard args
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81 0/subop/add 3/mod/direct 4/rm32/esp . . . . . 8/imm32 # add to esp
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# write-int(_test-stream, "efgh")
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# . . push args
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68/push 0x68676665/imm32
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68/push _test-stream/imm32
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# . . call
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e8/call write-int/disp32
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# . . discard args
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81 0/subop/add 3/mod/direct 4/rm32/esp . . . . . 8/imm32 # add to esp
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# check-stream-equal(_test-stream, "abcdefgh", msg)
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# . . push args
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68/push "F - test-write-byte-buffered-multiple"/imm32
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68/push "abcdefgh"/imm32
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68/push _test-stream/imm32
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# . . call
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e8/call check-stream-equal/disp32
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# . . discard args
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81 0/subop/add 3/mod/direct 4/rm32/esp . . . . . 0xc/imm32 # add to esp
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# . end
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c3/return
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# . . vim:nowrap:textwidth=0
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