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author | Kartik Agaram <vc@akkartik.com> | 2019-05-11 08:04:40 -0700 |
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committer | Kartik Agaram <vc@akkartik.com> | 2019-05-11 08:04:40 -0700 |
commit | 258f6b3a3a51f62851731cdb391b65667cde2993 (patch) | |
tree | ec4b36d44e4de9a02626e354785f5507a996a315 /subx/066print-int.subx | |
parent | 36c745f8e0cb24b781a5cb6bb7e829937dabec46 (diff) | |
download | mu-258f6b3a3a51f62851731cdb391b65667cde2993.tar.gz |
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Diffstat (limited to 'subx/066print-int.subx')
-rw-r--r-- | subx/066print-int.subx | 215 |
1 files changed, 215 insertions, 0 deletions
diff --git a/subx/066print-int.subx b/subx/066print-int.subx new file mode 100644 index 00000000..faac6e5c --- /dev/null +++ b/subx/066print-int.subx @@ -0,0 +1,215 @@ +# Print the (hex) textual representation of numbers. + +== code +# instruction effective address register displacement immediate +# . op subop mod rm32 base index scale r32 +# . 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 + +#? Entry: # run a single test, while debugging +#? e8/call test-print-int32/disp32 +#? # syscall(exit, Num-test-failures) +#? 8b/copy 0/mod/indirect 5/rm32/.disp32 . . 3/r32/EBX Num-test-failures/disp32 # copy *Num-test-failures to EBX +#? b8/copy-to-EAX 1/imm32/exit +#? cd/syscall 0x80/imm8 + +# print the hex representation for the lowest byte of a number +print-byte: # f : (address buffered-file), n : int -> <void> + # . prolog + 55/push-EBP + 89/copy 3/mod/direct 5/rm32/EBP . . . 4/r32/ESP . . # copy ESP to EBP + # . save registers + 50/push-EAX + # AL = convert upper nibble to hex + 8b/copy 1/mod/*+disp8 5/rm32/EBP . . . 0/r32/EAX 0xc/disp8 . # copy *(EBP+12) to EAX + c1/shift 5/subop/logic-right 3/mod/direct 0/rm32/EAX . . . . . 4/imm8 # shift EAX right by 4 bits, while padding zeroes + 25/and-EAX 0xf/imm32 + # . AL = to-hex-char(AL) + e8/call to-hex-char/disp32 + # write-byte(f, AL) + # . . push args + 50/push-EAX + ff 6/subop/push 1/mod/*+disp8 5/rm32/EBP . . . . 8/disp8 . # push *(EBP+8) + # . . call + e8/call write-byte/disp32 + # . . discard args + 81 0/subop/add 3/mod/direct 4/rm32/ESP . . . . . 8/imm32 # add to ESP + # AL = convert lower nibble to hex + 8b/copy 1/mod/*+disp8 5/rm32/EBP . . . 0/r32/EAX 0xc/disp8 . # copy *(EBP+12) to EAX + 25/and-EAX 0xf/imm32 + # . AL = to-hex-char(AL) + e8/call to-hex-char/disp32 + # write-byte(f, AL) + # . . push args + 50/push-EAX + ff 6/subop/push 1/mod/*+disp8 5/rm32/EBP . . . . 8/disp8 . # push *(EBP+8) + # . . call + e8/call write-byte/disp32 + # . . discard args + 81 0/subop/add 3/mod/direct 4/rm32/ESP . . . . . 8/imm32 # add to ESP +$print-byte:end: + # . restore registers + 58/pop-to-EAX + # . epilog + 89/copy 3/mod/direct 4/rm32/ESP . . . 5/r32/EBP . . # copy EBP to ESP + 5d/pop-to-EBP + c3/return + +test-print-byte: + # - check that print-byte prints the hex textual representation + # setup + # . clear-stream(_test-stream) + # . . push args + 68/push _test-stream/imm32 + # . . call + e8/call clear-stream/disp32 + # . . discard args + 81 0/subop/add 3/mod/direct 4/rm32/ESP . . . . . 4/imm32 # add to ESP + # . clear-stream(_test-buffered-file+4) + # . . push args + b8/copy-to-EAX _test-buffered-file/imm32 + 05/add-to-EAX 4/imm32 + 50/push-EAX + # . . call + e8/call clear-stream/disp32 + # . . discard args + 81 0/subop/add 3/mod/direct 4/rm32/ESP . . . . . 4/imm32 # add to ESP + # print-byte(_test-buffered-file, 0xa) # exercises digit, non-digit as well as leading zero + # . . push args + 68/push 0xa/imm32 + 68/push _test-buffered-file/imm32 + # . . call + e8/call print-byte/disp32 + # . . discard args + 81 0/subop/add 3/mod/direct 4/rm32/ESP . . . . . 8/imm32 # add to ESP + # flush(_test-buffered-file) + # . . push args + 68/push _test-buffered-file/imm32 + # . . call + e8/call flush/disp32 + # . . discard args + 81 0/subop/add 3/mod/direct 4/rm32/ESP . . . . . 4/imm32 # add to ESP + # check-stream-equal(_test-stream, "0a", msg) + # . . push args + 68/push "F - test-print-byte"/imm32 + 68/push "0a"/imm32 + 68/push _test-stream/imm32 + # . . call + e8/call check-stream-equal/disp32 + # . . discard args + 81 0/subop/add 3/mod/direct 4/rm32/ESP . . . . . 0xc/imm32 # add to ESP + # . end + c3/return + +print-int32: # f : (address buffered-file), n : int -> <void> + # pseudocode: + # ECX = 28 + # while true + # if (ECX < 0) break + # EAX = n >> ECX + # EAX = EAX & 0xf + # write-byte(f, AL) + # ECX -= 4 + # + # . prolog + 55/push-EBP + 89/copy 3/mod/direct 5/rm32/EBP . . . 4/r32/ESP . . # copy ESP to EBP + # . save registers + 50/push-EAX + 51/push-ECX + # ECX = 28 + b9/copy-to-ECX 0x1c/imm32 +$print-int32:loop: + # if (ECX < 0) break + 81 7/subop/compare 3/mod/direct 1/rm32/ECX . . . . . 0/imm32 # compare ECX + 7c/jump-if-lesser $print-int32:end/disp8 + # EAX = n >> ECX + 8b/copy 1/mod/*+disp8 5/rm32/EBP . . . 0/r32/EAX 0xc/disp8 . # copy *(EBP+12) to EAX + d3/>>ECX 5/subop/pad-zeroes 3/mod/direct 0/rm32/EAX . . . . . . # shift EAX right by ECX bits, padding zeroes + # EAX = to-hex-char(AL) + 25/and-EAX 0xf/imm32 + e8/call to-hex-char/disp32 + # write-byte(f, AL) + # . . push args + 50/push-EAX + ff 6/subop/push 1/mod/*+disp8 5/rm32/EBP . . . . 8/disp8 . # push *(EBP+8) + # . . call + e8/call write-byte/disp32 + # . . discard args + 81 0/subop/add 3/mod/direct 4/rm32/ESP . . . . . 8/imm32 # add to ESP + # ECX -= 4 + 81 5/subop/subtract 3/mod/direct 1/rm32/ECX . . . . . 4/imm32 # subtract from ECX + eb/jump $print-int32:loop/disp8 +$print-int32:end: + # . restore registers + 59/pop-to-ECX + 58/pop-to-EAX + # . epilog + 89/copy 3/mod/direct 4/rm32/ESP . . . 5/r32/EBP . . # copy EBP to ESP + 5d/pop-to-EBP + c3/return + +test-print-int32: + # - check that print-int32 prints the hex textual representation + # setup + # . clear-stream(_test-stream) + # . . push args + 68/push _test-stream/imm32 + # . . call + e8/call clear-stream/disp32 + # . . discard args + 81 0/subop/add 3/mod/direct 4/rm32/ESP . . . . . 4/imm32 # add to ESP + # . clear-stream(_test-buffered-file+4) + # . . push args + b8/copy-to-EAX _test-buffered-file/imm32 + 05/add-to-EAX 4/imm32 + 50/push-EAX + # . . call + e8/call clear-stream/disp32 + # . . discard args + 81 0/subop/add 3/mod/direct 4/rm32/ESP . . . . . 4/imm32 # add to ESP + # print-int32(_test-buffered-file, 0x8899aa) + # . . push args + 68/push 0x8899aa/imm32 + 68/push _test-buffered-file/imm32 + # . . call + e8/call print-int32/disp32 + # . . discard args + 81 0/subop/add 3/mod/direct 4/rm32/ESP . . . . . 8/imm32 # add to ESP + # flush(_test-buffered-file) + # . . push args + 68/push _test-buffered-file/imm32 + # . . call + e8/call flush/disp32 + # . . discard args + 81 0/subop/add 3/mod/direct 4/rm32/ESP . . . . . 4/imm32 # add to ESP +#? # dump line {{{ +#? # . write-stream(2/stderr, line) +#? # . . push args +#? 68/push _test-stream/imm32 +#? 68/push 2/imm32/stderr +#? # . . call +#? e8/call write-stream/disp32 +#? # . . discard args +#? 81 0/subop/add 3/mod/direct 4/rm32/ESP . . . . . 8/imm32 # add to ESP +#? # . write(2/stderr, "$\n") +#? # . . push args +#? 68/push "$\n"/imm32 +#? 68/push 2/imm32/stderr +#? # . . call +#? e8/call write/disp32 +#? # . . discard args +#? 81 0/subop/add 3/mod/direct 4/rm32/ESP . . . . . 8/imm32 # add to ESP +#? # }}} + # check-stream-equal(_test-stream, "008899aa", msg) + # . . push args + 68/push "F - test-print-int32"/imm32 + 68/push "008899aa"/imm32 + 68/push _test-stream/imm32 + # . . call + e8/call check-stream-equal/disp32 + # . . discard args + 81 0/subop/add 3/mod/direct 4/rm32/ESP . . . . . 0xc/imm32 # add to ESP + # . end + c3/return + +# . . vim:nowrap:textwidth=0 |