Mu - subx/066print-byte.subx

From 6e181e7fd998a0d542cb531c929c905a243ea2f6 Mon Sep 17 00:00:00 2001 From: Kartik Agaram Date: Tue, 5 Feb 2019 23:30:12 -0800 Subject: 4953 --- html/subx/066print-byte.subx.html | 167 ++++++++++++++++++++++++++++++++++++++ 1 file changed, 167 insertions(+) create mode 100644 html/subx/066print-byte.subx.html (limited to 'html/subx/066print-byte.subx.html') diff --git a/html/subx/066print-byte.subx.html b/html/subx/066print-byte.subx.html new file mode 100644 index 00000000..99fc717f --- /dev/null +++ b/html/subx/066print-byte.subx.html @@ -0,0 +1,167 @@ + + + + +Mu - subx/066print-byte.subx + + + + + + + + + + +https://github.com/akkartik/mu/blob/master/subx/066print-byte.subx +

+  1 # Print the (hex) textual representation of the lowest byte of a number.
+  2 
+  3 == code
+  4 #   instruction                     effective address                                                   register    displacement    immediate
+  5 # . op          subop               mod             rm32          base        index         scale       r32
+  6 # . 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
+  7 
+  8 # main:
+  9     e8/call  run-tests/disp32  # 'run-tests' is a function created automatically by SubX. It calls all functions that start with 'test-'.
+ 10     # syscall(exit, Num-test-failures)
+ 11     8b/copy                         0/mod/indirect  5/rm32/.disp32            .             .           3/r32/EBX   Num-test-failures/disp32          # copy *Num-test-failures to EBX
+ 12     b8/copy-to-EAX  1/imm32/exit
+ 13     cd/syscall  0x80/imm8
+ 14 
+ 15 print-byte:  # f : (address buffered-file), n : int -> <void>
+ 16     # . prolog
+ 17     55/push-EBP
+ 18     89/copy                         3/mod/direct    5/rm32/EBP    .           .             .           4/r32/ESP   .               .                 # copy ESP to EBP
+ 19     # . save registers
+ 20     50/push-EAX
+ 21     # AL = convert upper nibble to hex
+ 22     8b/copy                         1/mod/*+disp8   5/rm32/EBP    .           .             .           0/r32/EAX   0xc/disp8       .                 # copy *(EBP+12) to EAX
+ 23     c1/shift    5/subop/logic-right 3/mod/direct    0/rm32/EAX    .           .             .           .           .               4/imm8            # shift EAX right by 4 bits, while padding zeroes
+ 24     25/and-EAX  0xf/imm32
+ 25     # . AL = to-hex-char(AL)
+ 26     e8/call  to-hex-char/disp32
+ 27     # write-byte(f, AL)
+ 28     # . . push args
+ 29     50/push-EAX
+ 30     ff          6/subop/push        1/mod/*+disp8   5/rm32/EBP    .           .             .           .           8/disp8         .                 # push *(EBP+8)
+ 31     # . . call
+ 32     e8/call  write-byte/disp32
+ 33     # . . discard args
+ 34     81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               8/imm32           # add to ESP
+ 35     # AL = convert lower nibble to hex
+ 36     8b/copy                         1/mod/*+disp8   5/rm32/EBP    .           .             .           0/r32/EAX   0xc/disp8       .                 # copy *(EBP+12) to EAX
+ 37     25/and-EAX  0xf/imm32
+ 38     # . AL = to-hex-char(AL)
+ 39     e8/call  to-hex-char/disp32
+ 40     # write-byte(f, AL)
+ 41     # . . push args
+ 42     50/push-EAX
+ 43     ff          6/subop/push        1/mod/*+disp8   5/rm32/EBP    .           .             .           .           8/disp8         .                 # push *(EBP+8)
+ 44     # . . call
+ 45     e8/call  write-byte/disp32
+ 46     # . . discard args
+ 47     81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               8/imm32           # add to ESP
+ 48 $print-byte:end:
+ 49     # . restore registers
+ 50     58/pop-to-EAX
+ 51     # . epilog
+ 52     89/copy                         3/mod/direct    4/rm32/ESP    .           .             .           5/r32/EBP   .               .                 # copy EBP to ESP
+ 53     5d/pop-to-EBP
+ 54     c3/return
+ 55 
+ 56 test-print-byte:
+ 57     # - check that print-byte prints the hex textual representation
+ 58     # setup
+ 59     # . clear-stream(_test-stream)
+ 60     # . . push args
+ 61     68/push  _test-stream/imm32
+ 62     # . . call
+ 63     e8/call  clear-stream/disp32
+ 64     # . . discard args
+ 65     81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               4/imm32           # add to ESP
+ 66     # . clear-stream(_test-buffered-file+4)
+ 67     # . . push args
+ 68     b8/copy-to-EAX  _test-buffered-file/imm32
+ 69     05/add-to-EAX  4/imm32
+ 70     50/push-EAX
+ 71     # . . call
+ 72     e8/call  clear-stream/disp32
+ 73     # . . discard args
+ 74     81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               4/imm32           # add to ESP
+ 75     # print-byte(_test-buffered-file, 0xa)  # exercises digit, non-digit as well as leading zero
+ 76     # . . push args
+ 77     68/push  0xa/imm32
+ 78     68/push  _test-buffered-file/imm32
+ 79     # . . call
+ 80     e8/call  print-byte/disp32
+ 81     # . . discard args
+ 82     81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               8/imm32           # add to ESP
+ 83     # flush(_test-buffered-file)
+ 84     # . . push args
+ 85     68/push  _test-buffered-file/imm32
+ 86     # . . call
+ 87     e8/call  flush/disp32
+ 88     # . . discard args
+ 89     81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               4/imm32           # add to ESP
+ 90     # check-stream-equal(_test-stream, "0a", msg)
+ 91     # . . push args
+ 92     68/push  "F - test-print-byte"/imm32
+ 93     68/push  "0a"/imm32
+ 94     68/push  _test-stream/imm32
+ 95     # . . call
+ 96     e8/call  check-stream-equal/disp32
+ 97     # . . discard args
+ 98     81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               0xc/imm32         # add to ESP
+ 99     # . end
+100     c3/return
+101 
+102 # . . vim:nowrap:textwidth=0
+

+ + + -- cgit 1.4.1-2-gfad0