Mu - baremetal/117write-int-hex.subx

From 4254408a385f90ffe212e85a7b405054f4e73f5e Mon Sep 17 00:00:00 2001 From: Kartik Agaram Date: Sat, 23 Jan 2021 11:14:07 -0800 Subject: 7549 --- html/baremetal/117write-int-hex.subx.html | 266 ++++++++++++++++++++++++++++++ 1 file changed, 266 insertions(+) create mode 100644 html/baremetal/117write-int-hex.subx.html (limited to 'html/baremetal/117write-int-hex.subx.html') diff --git a/html/baremetal/117write-int-hex.subx.html b/html/baremetal/117write-int-hex.subx.html new file mode 100644 index 00000000..00b68fdd --- /dev/null +++ b/html/baremetal/117write-int-hex.subx.html @@ -0,0 +1,266 @@ + + + + +Mu - baremetal/117write-int-hex.subx + + + + + + + + + + +https://github.com/akkartik/mu/blob/main/baremetal/117write-int-hex.subx +
+  1 # Write out the (hex) textual representation of numbers.
+  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 # convert the lowest nibble of eax to ascii and return it in the lowest byte of eax
+  9 to-hex-char:  # in/eax: int -> out/eax: int
+ 10     # no error checking; accepts argument in eax
+ 11     # if (eax <= 9) return eax + '0'
+ 12     3d/compare-eax-with  0x9/imm32/9
+ 13     7f/jump-if->  $to-hex-char:else/disp8
+ 14     05/add-to-eax  0x30/imm32/0
+ 15     c3/return
+ 16 $to-hex-char:else:
+ 17     # otherwise return eax + 'a' - 10
+ 18     05/add-to-eax  0x57/imm32/a-10
+ 19     c3/return
+ 20 
+ 21 append-byte-hex:  # f: (addr stream byte), n: int
+ 22     # . prologue
+ 23     55/push-ebp
+ 24     89/copy                         3/mod/direct    5/rm32/ebp    .           .             .           4/r32/esp   .               .                 # copy esp to ebp
+ 25     # . save registers
+ 26     50/push-eax
+ 27     # AL = convert upper nibble to hex
+ 28     8b/copy                         1/mod/*+disp8   5/rm32/ebp    .           .             .           0/r32/eax   0xc/disp8       .                 # copy *(ebp+12) to eax
+ 29     c1/shift    5/subop/logic-right 3/mod/direct    0/rm32/eax    .           .             .           .           .               4/imm8            # shift eax right by 4 bits, while padding zeroes
+ 30     25/and-eax  0xf/imm32
+ 31     # . AL = to-hex-char(AL)
+ 32     e8/call  to-hex-char/disp32
+ 33     # append-byte(f, AL)
+ 34     # . . push args
+ 35     50/push-eax
+ 36     ff          6/subop/push        1/mod/*+disp8   5/rm32/ebp    .           .             .           .           8/disp8         .                 # push *(ebp+8)
+ 37     # . . call
+ 38     e8/call  append-byte/disp32
+ 39     # . . discard args
+ 40     81          0/subop/add         3/mod/direct    4/rm32/esp    .           .             .           .           .               8/imm32           # add to esp
+ 41     # AL = convert lower nibble to hex
+ 42     8b/copy                         1/mod/*+disp8   5/rm32/ebp    .           .             .           0/r32/eax   0xc/disp8       .                 # copy *(ebp+12) to eax
+ 43     25/and-eax  0xf/imm32
+ 44     # . AL = to-hex-char(AL)
+ 45     e8/call  to-hex-char/disp32
+ 46     # append-byte(f, AL)
+ 47     # . . push args
+ 48     50/push-eax
+ 49     ff          6/subop/push        1/mod/*+disp8   5/rm32/ebp    .           .             .           .           8/disp8         .                 # push *(ebp+8)
+ 50     # . . call
+ 51     e8/call  append-byte/disp32
+ 52     # . . discard args
+ 53     81          0/subop/add         3/mod/direct    4/rm32/esp    .           .             .           .           .               8/imm32           # add to esp
+ 54 $append-byte-hex:end:
+ 55     # . restore registers
+ 56     58/pop-to-eax
+ 57     # . epilogue
+ 58     89/copy                         3/mod/direct    4/rm32/esp    .           .             .           5/r32/ebp   .               .                 # copy ebp to esp
+ 59     5d/pop-to-ebp
+ 60     c3/return
+ 61 
+ 62 test-append-byte-hex:
+ 63     # - check that append-byte-hex adds the hex textual representation
+ 64     # setup
+ 65     # . clear-stream(_test-stream)
+ 66     # . . push args
+ 67     68/push  _test-stream/imm32
+ 68     # . . call
+ 69     e8/call  clear-stream/disp32
+ 70     # . . discard args
+ 71     81          0/subop/add         3/mod/direct    4/rm32/esp    .           .             .           .           .               4/imm32           # add to esp
+ 72     # append-byte-hex(_test-stream, 0xa)  # exercises digit, non-digit as well as leading zero
+ 73     # . . push args
+ 74     68/push  0xa/imm32
+ 75     68/push  _test-stream/imm32
+ 76     # . . call
+ 77     e8/call  append-byte-hex/disp32
+ 78     # . . discard args
+ 79     81          0/subop/add         3/mod/direct    4/rm32/esp    .           .             .           .           .               8/imm32           # add to esp
+ 80     # check-stream-equal(_test-stream, "0a", msg)
+ 81     # . . push args
+ 82     68/push  "F - test-append-byte-hex"/imm32
+ 83     68/push  "0a"/imm32
+ 84     68/push  _test-stream/imm32
+ 85     # . . call
+ 86     e8/call  check-stream-equal/disp32
+ 87     # . . discard args
+ 88     81          0/subop/add         3/mod/direct    4/rm32/esp    .           .             .           .           .               0xc/imm32         # add to esp
+ 89     # . end
+ 90     c3/return
+ 91 
+ 92 write-int32-hex:  # f: (addr stream byte), n: int
+ 93     # . prologue
+ 94     55/push-ebp
+ 95     89/copy                         3/mod/direct    5/rm32/ebp    .           .             .           4/r32/esp   .               .                 # copy esp to ebp
+ 96 $write-int32-hex:hex-prefix:
+ 97     # write(f, "0x")
+ 98     # . . push args
+ 99     68/push  "0x"/imm32
+100     ff          6/subop/push        1/mod/*+disp8   5/rm32/ebp    .           .             .           .           8/disp8         .                 # push *(ebp+8)
+101     # . . call
+102     e8/call  write/disp32
+103     # . . discard args
+104     81          0/subop/add         3/mod/direct    4/rm32/esp    .           .             .           .           .               8/imm32           # add to esp
+105 $write-int32-hex:rest:
+106     # write-int32-hex-bits(f, n, 32)
+107     # . . push args
+108     68/push  0x20/imm32
+109     ff          6/subop/push        1/mod/*+disp8   5/rm32/ebp    .           .             .           .           0xc/disp8       .                 # push *(ebp+12)
+110     ff          6/subop/push        1/mod/*+disp8   5/rm32/ebp    .           .             .           .           8/disp8         .                 # push *(ebp+8)
+111     # . . call
+112     e8/call  write-int32-hex-bits/disp32
+113     # . . discard args
+114     81          0/subop/add         3/mod/direct    4/rm32/esp    .           .             .           .           .               0xc/imm32         # add to esp
+115 $write-int32-hex:end:
+116     # . epilogue
+117     89/copy                         3/mod/direct    4/rm32/esp    .           .             .           5/r32/ebp   .               .                 # copy ebp to esp
+118     5d/pop-to-ebp
+119     c3/return
+120 
+121 # print rightmost 'bits' of 'n'
+122 # bits must be multiple of 4
+123 write-int32-hex-bits:  # f: (addr stream byte), n: int, bits: int
+124     # pseudocode:
+125     #  bits -= 4
+126     #  while true
+127     #    if (bits < 0) break
+128     #    eax = n >> bits
+129     #    eax = eax & 0xf
+130     #    append-byte(f, AL)
+131     #    bits -= 4
+132     #
+133     # . prologue
+134     55/push-ebp
+135     89/copy                         3/mod/direct    5/rm32/ebp    .           .             .           4/r32/esp   .               .                 # copy esp to ebp
+136     # . save registers
+137     50/push-eax
+138     51/push-ecx
+139     # ecx = bits-4
+140     8b/copy                         1/mod/*+disp8   5/rm32/ebp    .           .             .           1/r32/ecx   0x10/disp8      .                 # copy *(ebp+16) to ecx
+141     81          5/subop/subtract    3/mod/direct    1/rm32/ecx    .           .             .           .           .               4/imm32           # subtract from ecx
+142 $write-int32-hex-bits:loop:
+143     # if (bits < 0) break
+144     81          7/subop/compare     3/mod/direct    1/rm32/ecx    .           .             .           .           .               0/imm32           # compare ecx
+145     7c/jump-if-<  $write-int32-hex-bits:end/disp8
+146     # eax = n >> bits
+147     8b/copy                         1/mod/*+disp8   5/rm32/ebp    .           .             .           0/r32/eax   0xc/disp8       .                 # copy *(ebp+12) to eax
+148     d3/>>ecx    5/subop/pad-zeroes  3/mod/direct    0/rm32/eax    .           .             .           .           .               .                 # shift eax right by ecx bits, padding zeroes
+149     # eax = to-hex-char(AL)
+150     25/and-eax  0xf/imm32
+151     e8/call  to-hex-char/disp32
+152     # append-byte(f, AL)
+153     # . . push args
+154     50/push-eax
+155     ff          6/subop/push        1/mod/*+disp8   5/rm32/ebp    .           .             .           .           8/disp8         .                 # push *(ebp+8)
+156     # . . call
+157     e8/call  append-byte/disp32
+158     # . . discard args
+159     81          0/subop/add         3/mod/direct    4/rm32/esp    .           .             .           .           .               8/imm32           # add to esp
+160     # bits -= 4
+161     81          5/subop/subtract    3/mod/direct    1/rm32/ecx    .           .             .           .           .               4/imm32           # subtract from ecx
+162     eb/jump  $write-int32-hex-bits:loop/disp8
+163 $write-int32-hex-bits:end:
+164     # . restore registers
+165     59/pop-to-ecx
+166     58/pop-to-eax
+167     # . epilogue
+168     89/copy                         3/mod/direct    4/rm32/esp    .           .             .           5/r32/ebp   .               .                 # copy ebp to esp
+169     5d/pop-to-ebp
+170     c3/return
+171 
+172 test-write-int32-hex:
+173     # - check that write-int32-hex prints the hex textual representation
+174     # setup
+175     # . clear-stream(_test-stream)
+176     # . . push args
+177     68/push  _test-stream/imm32
+178     # . . call
+179     e8/call  clear-stream/disp32
+180     # . . discard args
+181     81          0/subop/add         3/mod/direct    4/rm32/esp    .           .             .           .           .               4/imm32           # add to esp
+182     # write-int32-hex(_test-stream, 0x8899aa)
+183     # . . push args
+184     68/push  0x8899aa/imm32
+185     68/push  _test-stream/imm32
+186     # . . call
+187     e8/call  write-int32-hex/disp32
+188     # . . discard args
+189     81          0/subop/add         3/mod/direct    4/rm32/esp    .           .             .           .           .               8/imm32           # add to esp
+190     # check-stream-equal(_test-stream, "0x008899aa", msg)
+191     # . . push args
+192     68/push  "F - test-write-int32-hex"/imm32
+193     68/push  "0x008899aa"/imm32
+194     68/push  _test-stream/imm32
+195     # . . call
+196     e8/call  check-stream-equal/disp32
+197     # . . discard args
+198     81          0/subop/add         3/mod/direct    4/rm32/esp    .           .             .           .           .               0xc/imm32         # add to esp
+199     # . end
+200     c3/return
+201 
+202 # . . vim:nowrap:textwidth=0
+
+ + + -- cgit 1.4.1-2-gfad0