Mu - baremetal/126write-int-decimal.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/126write-int-decimal.subx.html | 468 ++++++++++++++++++++++++++ 1 file changed, 468 insertions(+) create mode 100644 html/baremetal/126write-int-decimal.subx.html (limited to 'html/baremetal/126write-int-decimal.subx.html') diff --git a/html/baremetal/126write-int-decimal.subx.html b/html/baremetal/126write-int-decimal.subx.html new file mode 100644 index 00000000..e1c786ea --- /dev/null +++ b/html/baremetal/126write-int-decimal.subx.html @@ -0,0 +1,468 @@ + + + + +Mu - baremetal/126write-int-decimal.subx + + + + + + + + + + +https://github.com/akkartik/mu/blob/main/baremetal/126write-int-decimal.subx +
+  1 # Helper to print an int32 in decimal.
+  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 write-int32-decimal:  # out: (addr stream byte), n: int
+  9     # works by generating characters from lowest to highest and pushing them
+ 10     # to the stack, before popping them one by one into the stream
+ 11     #
+ 12     # pseudocode:
+ 13     #   push sentinel
+ 14     #   eax = abs(n)
+ 15     #   while true
+ 16     #     sign-extend eax into edx
+ 17     #     eax, edx = eax/10, eax%10
+ 18     #     edx += '0'
+ 19     #     push edx
+ 20     #     if (eax == 0) break
+ 21     #   if n < 0
+ 22     #     push '-'
+ 23     #   w = out->write
+ 24     #   curr = &out->data[out->write]
+ 25     #   max = &out->data[out->size]
+ 26     #   while true
+ 27     #     pop into eax
+ 28     #     if (eax == sentinel) break
+ 29     #     if (curr >= max) abort
+ 30     #     *curr = AL
+ 31     #     ++curr
+ 32     #     ++w
+ 33     #   out->write = w
+ 34     # (based on K&R itoa: https://en.wikibooks.org/wiki/C_Programming/stdlib.h/itoa)
+ 35     # (this pseudocode contains registers because operations like division
+ 36     # require specific registers in x86)
+ 37     #
+ 38     # . prologue
+ 39     55/push-ebp
+ 40     89/copy                         3/mod/direct    5/rm32/ebp    .           .             .           4/r32/esp   .               .                 # copy esp to ebp
+ 41     # . save registers
+ 42     50/push-eax
+ 43     51/push-ecx
+ 44     52/push-edx
+ 45     53/push-ebx
+ 46     57/push-edi
+ 47     # const ten/ecx = 10
+ 48     b9/copy-to-ecx  0xa/imm32
+ 49     # push sentinel
+ 50     68/push  0/imm32/sentinel
+ 51     # var eax: int = abs(n)
+ 52     8b/copy                         1/mod/*+disp8   5/rm32/ebp    .           .             .           0/r32/eax   0xc/disp8       .                 # copy *(ebp+12) to eax
+ 53     3d/compare-eax-with  0/imm32
+ 54     7d/jump-if->=  $write-int32-decimal:read-loop/disp8
+ 55 $write-int32-decimal:negative:
+ 56     f7          3/subop/negate      3/mod/direct    0/rm32/eax    .           .             .           .           .               .                 # negate eax
+ 57 $write-int32-decimal:read-loop:
+ 58     # eax, edx = eax / 10, eax % 10
+ 59     99/sign-extend-eax-into-edx
+ 60     f7          7/subop/idiv        3/mod/direct    1/rm32/ecx    .           .             .           .           .               .                 # divide edx:eax by ecx, storing quotient in eax and remainder in edx
+ 61     # edx += '0'
+ 62     81          0/subop/add         3/mod/direct    2/rm32/edx    .           .             .           .           .               0x30/imm32        # add to edx
+ 63     # push edx
+ 64     52/push-edx
+ 65     # if (eax == 0) break
+ 66     3d/compare-eax-and  0/imm32
+ 67     7f/jump-if->  $write-int32-decimal:read-loop/disp8
+ 68 $write-int32-decimal:read-break:
+ 69     # if (n < 0) push('-')
+ 70     81          7/subop/compare     1/mod/*+disp8   5/rm32/ebp    .           .             .           .           0xc/disp8       0/imm32           # compare *(ebp+12)
+ 71     7d/jump-if->=  $write-int32-decimal:write/disp8
+ 72 $write-int32-decimal:push-negative:
+ 73     68/push  0x2d/imm32/-
+ 74 $write-int32-decimal:write:
+ 75     # edi = out
+ 76     8b/copy                         1/mod/*+disp8   5/rm32/ebp    .           .             .           7/r32/edi   8/disp8         .                 # copy *(ebp+8) to edi
+ 77     # var w/edx: int = out->write
+ 78     8b/copy                         0/mod/indirect  7/rm32/edi    .           .             .           2/r32/edx   .               .                 # copy *edi to edx
+ 79     # var curr/ecx: (addr byte) = &out->data[out->write]
+ 80     8d/copy-address                 1/mod/*+disp8   4/rm32/sib    7/base/edi  2/index/edx   .           1/r32/ecx   0xc/disp8       .                 # copy ebx+edx+12 to ecx
+ 81     # var max/ebx: (addr byte) = &out->data[out->size]
+ 82     8b/copy                         1/mod/*+disp8   7/rm32/edi    .           .             .           3/r32/ebx   8/disp8         .                 # copy *(edi+8) to ebx
+ 83     8d/copy-address                 1/mod/*+disp8   4/rm32/sib    7/base/edi  3/index/ebx   .           3/r32/ebx   0xc/disp8       .                 # copy edi+ebx+12 to ebx
+ 84 $write-int32-decimal:write-loop:
+ 85     # pop into eax
+ 86     58/pop-to-eax
+ 87     # if (eax == sentinel) break
+ 88     3d/compare-eax-and  0/imm32/sentinel
+ 89     74/jump-if-=  $write-int32-decimal:write-break/disp8
+ 90     # if (curr >= max) abort
+ 91     39/compare                      3/mod/direct    1/rm32/ecx    .           .             .           3/r32/ebx   .               .                 # compare ecx with ebx
+ 92     73/jump-if-addr>=  $write-int32-decimal:abort/disp8
+ 93 $write-int32-decimal:write-char:
+ 94     # *curr = AL
+ 95     88/copy-byte                    0/mod/indirect  1/rm32/ecx    .           .             .           0/r32/AL    .               .                 # copy AL to byte at *ecx
+ 96     # ++curr
+ 97     41/increment-ecx
+ 98     # ++w
+ 99     42/increment-edx
+100     eb/jump  $write-int32-decimal:write-loop/disp8
+101 $write-int32-decimal:write-break:
+102     # out->write = w
+103     89/copy                         0/mod/indirect  7/rm32/edi    .           .             .           2/r32/edx   .               .                 # copy edx to *edi
+104 $write-int32-decimal:end:
+105     # . restore registers
+106     5f/pop-to-edi
+107     5b/pop-to-ebx
+108     5a/pop-to-edx
+109     59/pop-to-ecx
+110     58/pop-to-eax
+111     # . epilogue
+112     89/copy                         3/mod/direct    4/rm32/esp    .           .             .           5/r32/ebp   .               .                 # copy ebp to esp
+113     5d/pop-to-ebp
+114     c3/return
+115 
+116 $write-int32-decimal:abort:
+117     (draw-text-wrapping-right-then-down-from-cursor-over-full-screen 0 "write-int32-decimal: stream out of space" 3)  # 3=cyan
+118     {
+119       eb/jump loop/disp8
+120     }
+121     # never gets here
+122 
+123 test-write-int32-decimal:
+124     # - check that a single-digit number converts correctly
+125     # setup
+126     # . clear-stream(_test-stream)
+127     # . . push args
+128     68/push  _test-stream/imm32
+129     # . . call
+130     e8/call  clear-stream/disp32
+131     # . . discard args
+132     81          0/subop/add         3/mod/direct    4/rm32/esp    .           .             .           .           .               4/imm32           # add to esp
+133     # write-int32-decimal(_test-stream, 9)
+134     # . . push args
+135     68/push  9/imm32
+136     68/push  _test-stream/imm32
+137     # . . call
+138     e8/call  write-int32-decimal/disp32
+139     # . . discard args
+140     81          0/subop/add         3/mod/direct    4/rm32/esp    .           .             .           .           .               8/imm32           # add to esp
+141     # check-stream-equal(_test-stream, "9", msg)
+142     # . . push args
+143     68/push  "F - test-write-int32-decimal"/imm32
+144     68/push  "9"/imm32
+145     68/push  _test-stream/imm32
+146     # . . call
+147     e8/call  check-stream-equal/disp32
+148     # . . discard args
+149     81          0/subop/add         3/mod/direct    4/rm32/esp    .           .             .           .           .               0xc/imm32         # add to esp
+150     # . end
+151     c3/return
+152 
+153 test-write-int32-decimal-zero:
+154     # - check that 0 converts correctly
+155     # setup
+156     # . clear-stream(_test-stream)
+157     # . . push args
+158     68/push  _test-stream/imm32
+159     # . . call
+160     e8/call  clear-stream/disp32
+161     # . . discard args
+162     81          0/subop/add         3/mod/direct    4/rm32/esp    .           .             .           .           .               4/imm32           # add to esp
+163     # write-int32-decimal(_test-stream, 0)
+164     # . . push args
+165     68/push  0/imm32
+166     68/push  _test-stream/imm32
+167     # . . call
+168     e8/call  write-int32-decimal/disp32
+169     # . . discard args
+170     81          0/subop/add         3/mod/direct    4/rm32/esp    .           .             .           .           .               8/imm32           # add to esp
+171     # check-stream-equal(_test-stream, "0", msg)
+172     # . . push args
+173     68/push  "F - test-write-int32-decimal-zero"/imm32
+174     68/push  "0"/imm32
+175     68/push  _test-stream/imm32
+176     # . . call
+177     e8/call  check-stream-equal/disp32
+178     # . . discard args
+179     81          0/subop/add         3/mod/direct    4/rm32/esp    .           .             .           .           .               0xc/imm32         # add to esp
+180     # . end
+181     c3/return
+182 
+183 test-write-int32-decimal-multiple-digits:
+184     # - check that a multi-digit number converts correctly
+185     # setup
+186     # . clear-stream(_test-stream)
+187     # . . push args
+188     68/push  _test-stream/imm32
+189     # . . call
+190     e8/call  clear-stream/disp32
+191     # . . discard args
+192     81          0/subop/add         3/mod/direct    4/rm32/esp    .           .             .           .           .               4/imm32           # add to esp
+193     # write-int32-decimal(_test-stream, 10)
+194     # . . push args
+195     68/push  0xa/imm32
+196     68/push  _test-stream/imm32
+197     # . . call
+198     e8/call  write-int32-decimal/disp32
+199     # . . discard args
+200     81          0/subop/add         3/mod/direct    4/rm32/esp    .           .             .           .           .               8/imm32           # add to esp
+201     # check-stream-equal(_test-stream, "10", msg)
+202     # . . push args
+203     68/push  "F - test-write-int32-decimal-multiple-digits"/imm32
+204     68/push  "10"/imm32
+205     68/push  _test-stream/imm32
+206     # . . call
+207     e8/call  check-stream-equal/disp32
+208     # . . discard args
+209     81          0/subop/add         3/mod/direct    4/rm32/esp    .           .             .           .           .               0xc/imm32         # add to esp
+210     # . end
+211     c3/return
+212 
+213 test-write-int32-decimal-negative:
+214     # - check that a negative single-digit number converts correctly
+215     # setup
+216     # . clear-stream(_test-stream)
+217     # . . push args
+218     68/push  _test-stream/imm32
+219     # . . call
+220     e8/call  clear-stream/disp32
+221     # . . discard args
+222     81          0/subop/add         3/mod/direct    4/rm32/esp    .           .             .           .           .               4/imm32           # add to esp
+223     # write-int32-decimal(_test-stream, -9)
+224     # . . push args
+225     68/push  -9/imm32
+226     68/push  _test-stream/imm32
+227     # . . call
+228     e8/call  write-int32-decimal/disp32
+229     # . . discard args
+230     81          0/subop/add         3/mod/direct    4/rm32/esp    .           .             .           .           .               8/imm32           # add to esp
+231 +-- 26 lines: #?     # dump _test-stream ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------
+257     # check-stream-equal(_test-stream, "-9", msg)
+258     # . . push args
+259     68/push  "F - test-write-int32-decimal-negative"/imm32
+260     68/push  "-9"/imm32
+261     68/push  _test-stream/imm32
+262     # . . call
+263     e8/call  check-stream-equal/disp32
+264     # . . discard args
+265     81          0/subop/add         3/mod/direct    4/rm32/esp    .           .             .           .           .               0xc/imm32         # add to esp
+266     # . end
+267     c3/return
+268 
+269 test-write-int32-decimal-negative-multiple-digits:
+270     # - check that a multi-digit number converts correctly
+271     # setup
+272     # . clear-stream(_test-stream)
+273     # . . push args
+274     68/push  _test-stream/imm32
+275     # . . call
+276     e8/call  clear-stream/disp32
+277     # . . discard args
+278     81          0/subop/add         3/mod/direct    4/rm32/esp    .           .             .           .           .               4/imm32           # add to esp
+279     # write-int32-decimal(_test-stream, -10)
+280     # . . push args
+281     68/push  -0xa/imm32
+282     68/push  _test-stream/imm32
+283     # . . call
+284     e8/call  write-int32-decimal/disp32
+285     # . . discard args
+286     81          0/subop/add         3/mod/direct    4/rm32/esp    .           .             .           .           .               8/imm32           # add to esp
+287     # check-stream-equal(_test-stream, "-10", msg)
+288     # . . push args
+289     68/push  "F - test-write-int32-decimal-negative-multiple-digits"/imm32
+290     68/push  "-10"/imm32
+291     68/push  _test-stream/imm32
+292     # . . call
+293     e8/call  check-stream-equal/disp32
+294     # . . discard args
+295     81          0/subop/add         3/mod/direct    4/rm32/esp    .           .             .           .           .               0xc/imm32         # add to esp
+296     # . end
+297     c3/return
+298 
+299 is-decimal-digit?:  # c: grapheme -> result/eax: boolean
+300     # . prologue
+301     55/push-ebp
+302     89/copy                         3/mod/direct    5/rm32/ebp    .           .             .           4/r32/esp   .               .                 # copy esp to ebp
+303     # . save registers
+304     51/push-ecx
+305     # ecx = c
+306     8b/copy                         1/mod/*+disp8   5/rm32/ebp    .           .             .           1/r32/ecx   8/disp8         .                 # copy *(ebp+8) to ecx
+307     # result = false
+308     b8/copy-to-eax  0/imm32/false
+309     # return false if c < '0'
+310     81          7/subop/compare     3/mod/direct    1/rm32/ecx    .           .             .           .           .               0x30/imm32        # compare ecx
+311     7c/jump-if-<  $is-decimal-digit?:end/disp8
+312     # return (c <= '9')
+313     81          7/subop/compare     3/mod/direct    1/rm32/ecx    .           .             .           .           .               0x39/imm32        # compare ecx
+314     7f/jump-if->  $is-decimal-digit?:end/disp8
+315 $is-decimal-digit?:true:
+316     b8/copy-to-eax  1/imm32/true
+317 $is-decimal-digit?:end:
+318     # . restore registers
+319     59/pop-to-ecx
+320     # . epilogue
+321     89/copy                         3/mod/direct    4/rm32/esp    .           .             .           5/r32/ebp   .               .                 # copy ebp to esp
+322     5d/pop-to-ebp
+323     c3/return
+324 
+325 test-is-decimal-digit-below-0:
+326     # eax = is-decimal-digit?(0x2f)
+327     # . . push args
+328     68/push  0x2f/imm32
+329     # . . call
+330     e8/call  is-decimal-digit?/disp32
+331     # . . discard args
+332     81          0/subop/add         3/mod/direct    4/rm32/esp    .           .             .           .           .               4/imm32           # add to esp
+333     # check-ints-equal(eax, 0, msg)
+334     # . . push args
+335     68/push  "F - test-is-decimal-digit-below-0"/imm32
+336     68/push  0/imm32/false
+337     50/push-eax
+338     # . . call
+339     e8/call  check-ints-equal/disp32
+340     # . . discard args
+341     81          0/subop/add         3/mod/direct    4/rm32/esp    .           .             .           .           .               0xc/imm32         # add to esp
+342     c3/return
+343 
+344 test-is-decimal-digit-0-to-9:
+345     # eax = is-decimal-digit?(0x30)
+346     # . . push args
+347     68/push  0x30/imm32
+348     # . . call
+349     e8/call  is-decimal-digit?/disp32
+350     # . . discard args
+351     81          0/subop/add         3/mod/direct    4/rm32/esp    .           .             .           .           .               4/imm32           # add to esp
+352     # check-ints-equal(eax, 1, msg)
+353     # . . push args
+354     68/push  "F - test-is-decimal-digit-at-0"/imm32
+355     68/push  1/imm32/true
+356     50/push-eax
+357     # . . call
+358     e8/call  check-ints-equal/disp32
+359     # . . discard args
+360     81          0/subop/add         3/mod/direct    4/rm32/esp    .           .             .           .           .               0xc/imm32         # add to esp
+361     # eax = is-decimal-digit?(0x39)
+362     # . . push args
+363     68/push  0x39/imm32
+364     # . . call
+365     e8/call  is-decimal-digit?/disp32
+366     # . . discard args
+367     81          0/subop/add         3/mod/direct    4/rm32/esp    .           .             .           .           .               4/imm32           # add to esp
+368     # check-ints-equal(eax, 1, msg)
+369     # . . push args
+370     68/push  "F - test-is-decimal-digit-at-9"/imm32
+371     68/push  1/imm32/true
+372     50/push-eax
+373     # . . call
+374     e8/call  check-ints-equal/disp32
+375     # . . discard args
+376     81          0/subop/add         3/mod/direct    4/rm32/esp    .           .             .           .           .               0xc/imm32         # add to esp
+377     c3/return
+378 
+379 test-is-decimal-digit-above-9:
+380     # eax = is-decimal-digit?(0x3a)
+381     # . . push args
+382     68/push  0x3a/imm32
+383     # . . call
+384     e8/call  is-decimal-digit?/disp32
+385     # . . discard args
+386     81          0/subop/add         3/mod/direct    4/rm32/esp    .           .             .           .           .               4/imm32           # add to esp
+387     # check-ints-equal(eax, 0, msg)
+388     # . . push args
+389     68/push  "F - test-is-decimal-digit-above-9"/imm32
+390     68/push  0/imm32/false
+391     50/push-eax
+392     # . . call
+393     e8/call  check-ints-equal/disp32
+394     # . . discard args
+395     81          0/subop/add         3/mod/direct    4/rm32/esp    .           .             .           .           .               0xc/imm32         # add to esp
+396     c3/return
+397 
+398 to-decimal-digit:  # in: grapheme -> out/eax: int
+399     # . prologue
+400     55/push-ebp
+401     89/copy                         3/mod/direct    5/rm32/ebp    .           .             .           4/r32/esp   .               .                 # copy esp to ebp
+402     # eax = in
+403     8b/copy                         1/mod/*+disp8   5/rm32/ebp    .           .             .           0/r32/eax   8/disp8         .                 # copy *(ebp+8) to eax
+404 $to-decimal-digit:check0:
+405     # if (eax < '0') goto abort
+406     3d/compare-eax-with  0x30/imm32/0
+407     7c/jump-if-<  $to-decimal-digit:abort/disp8
+408 $to-decimal-digit:check1:
+409     # if (eax > '9') goto abort
+410     3d/compare-eax-with  0x39/imm32/f
+411     7f/jump-if->  $to-decimal-digit:abort/disp8
+412 $to-decimal-digit:digit:
+413     # return eax - '0'
+414     2d/subtract-from-eax  0x30/imm32/0
+415 $to-decimal-digit:end:
+416     # . epilogue
+417     89/copy                         3/mod/direct    4/rm32/esp    .           .             .           5/r32/ebp   .               .                 # copy ebp to esp
+418     5d/pop-to-ebp
+419     c3/return
+420 
+421 $to-decimal-digit:abort:
+422     (draw-text-wrapping-right-then-down-from-cursor-over-full-screen 0 "to-decimal-digit: not a digit character" 3)  # 3=cyan
+423     {
+424       eb/jump loop/disp8
+425     }
+426     # never gets here
+427 
+428 # . . vim:nowrap:textwidth=0
+
+ + + -- cgit 1.4.1-2-gfad0