6612 - reorganize layers

1 files changed, 416 insertions, 0 deletions

diff --git a/203stack.subx b/203stack.subx
new file mode 100644
index 00000000..0ab80b99
--- /dev/null
+++ b/203stack.subx
@@ -0,0 +1,416 @@
+# A stack looks like this:
+#   top: int
+#   data: (array byte)  # prefixed by size as usual
+#
+# TODO: is it confusing that the push opcodes grow memory downward, but the
+# push function grows stacks upward?
+
+== 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
+
+clear-stack:  # s: (addr stack)
+    # . prologue
+    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
+    # eax = s
+    8b/copy                         1/mod/*+disp8   5/rm32/ebp    .           .             .           0/r32/eax   8/disp8         .                 # copy *(ebp+8) to eax
+    # var max/ecx: (addr byte) = &s->data[s->size]
+    8b/copy                         1/mod/*+disp8   0/rm32/eax    .           .             .           1/r32/ecx   4/disp8         .                 # copy *(eax+4) to eax
+    8d/copy-address                 1/mod/*+disp8   4/rm32/sib    0/base/eax  1/index/ecx   .           1/r32/ecx   8/disp8         .                 # copy eax+ecx+8 to ecx
+    # s->top = 0
+    c7          0/subop/copy        0/mod/direct    0/rm32/eax    .           .             .           .           .               0/imm32           # copy to *eax
+    # var curr/eax: (addr byte) = s->data
+    81          0/subop/add         3/mod/direct    0/rm32/eax    .           .             .           .           .               8/imm32           # add to eax
+$clear-stack:loop:
+    # if (curr >= max) break
+    39/compare                      3/mod/direct    0/rm32/eax    .           .             .           1/r32/ecx   .               .                 # compare eax with ecx
+    73/jump-if-addr>=  $clear-stack:end/disp8
+    # *curr = 0
+    c6          0/subop/copy        0/mod/direct    0/rm32/eax    .           .             .           .           .               0/imm8            # copy byte to *eax
+    # ++curr
+    40/increment-eax
+    eb/jump $clear-stack:loop/disp8
+$clear-stack:end:
+    # . restore registers
+    59/pop-to-ecx
+    58/pop-to-eax
+    # . epilogue
+    89/copy                         3/mod/direct    4/rm32/esp    .           .             .           5/r32/ebp   .               .                 # copy ebp to esp
+    5d/pop-to-ebp
+    c3/return
+
+test-clear-stack:
+    # . prologue
+    55/push-ebp
+    89/copy                         3/mod/direct    5/rm32/ebp    .           .             .           4/r32/esp   .               .                 # copy esp to ebp
+    # var stack/ecx = stack of size 8 with random data in it
+    68/push 34/imm32
+    68/push 35/imm32
+    68/push 8/imm32/size
+    68/push 14/imm32/top
+    89/copy                         3/mod/direct    1/rm32/ecx    .           .             .           4/r32/esp   .               .                 # copy esp to ecx
+    # clear(stack)
+    # . . push args
+    51/push-ecx
+    # . . call
+    e8/call  clear-stack/disp32
+    # . . discard args
+    81          0/subop/add         3/mod/direct    4/rm32/esp    .           .             .           .           .               4/imm32           # add to esp
+    # top should be 0
+    58/pop-to-eax
+    # . check-ints-equal(eax, 0, msg)
+    # . . push args
+    68/push  "F - test-clear-stack: top"/imm32
+    68/push  0/imm32
+    50/push-eax
+    # . . call
+    e8/call  check-ints-equal/disp32
+    # . . discard args
+    81          0/subop/add         3/mod/direct    4/rm32/esp    .           .             .           .           .               0xc/imm32         # add to esp
+    # size should remain 8
+    58/pop-to-eax
+    # . check-ints-equal(eax, 8, msg)
+    # . . push args
+    68/push  "F - test-clear-stack: size"/imm32
+    68/push  8/imm32
+    50/push-eax
+    # . . call
+    e8/call  check-ints-equal/disp32
+    # . . discard args
+    81          0/subop/add         3/mod/direct    4/rm32/esp    .           .             .           .           .               0xc/imm32         # add to esp
+    # first word is 0
+    58/pop-to-eax
+    # . check-ints-equal(eax, 0, msg)
+    # . . push args
+    68/push  "F - test-clear-stack: data[0..3]"/imm32
+    68/push  0/imm32
+    50/push-eax
+    # . . call
+    e8/call  check-ints-equal/disp32
+    # . . discard args
+    81          0/subop/add         3/mod/direct    4/rm32/esp    .           .             .           .           .               0xc/imm32         # add to esp
+    # second word is 0
+    58/pop-to-eax
+    # . check-ints-equal(eax, 0, msg)
+    # . . push args
+    68/push  "F - test-clear-stack: data[4..7]"/imm32
+    68/push  0/imm32
+    50/push-eax
+    # . . call
+    e8/call  check-ints-equal/disp32
+    # . . discard args
+    81          0/subop/add         3/mod/direct    4/rm32/esp    .           .             .           .           .               0xc/imm32         # add to esp
+    # . epilogue
+    89/copy                         3/mod/direct    4/rm32/esp    .           .             .           5/r32/ebp   .               .                 # copy ebp to esp
+    5d/pop-to-ebp
+    c3/return
+
+# TODO: make this generic
+push:  # s: (addr stack), n: int
+    # . prologue
+    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
+    56/push-esi
+    # esi = s
+    8b/copy                         1/mod/*+disp8   5/rm32/ebp    .           .             .           6/r32/esi   8/disp8         .                 # copy *(ebp+8) to esi
+    # ecx = s->top
+    8b/copy                         0/mod/indirect  6/rm32/esi    .           .             .           1/r32/ecx   .               .                 # copy *esi to ecx
+    # if (s->top >= s->size) abort
+    39/compare                      1/mod/*+disp8   6/rm32/esi    .           .             .           1/r32/ecx   4/disp8         .                 # compare *(esi+4) and ecx
+    7e/jump-if-<=  $push:abort/disp8
+    # s->data[s->top] = n
+    8b/copy                         1/mod/*+disp8   5/rm32/ebp    .           .             .           0/r32/eax   0xc/disp8       .                 # copy *(ebp+12) to eax
+    89/copy                         1/mod/*+disp8   4/rm32/sib    6/base/esi  1/index/ecx   .           0/r32/eax   8/disp8         .                 # copy eax to *(esi+ecx+8)
+    # s->top += 4
+    81          0/subop/add         0/mod/direct    6/rm32/esi    .           .             .           .           .               4/imm32           # subtract from *esi
+$push:end:
+    # . restore registers
+    5e/pop-to-esi
+    59/pop-to-ecx
+    58/pop-to-eax
+    # . epilogue
+    89/copy                         3/mod/direct    4/rm32/esp    .           .             .           5/r32/ebp   .               .                 # copy ebp to esp
+    5d/pop-to-ebp
+    c3/return
+
+$push:abort:
+    # print(stderr, "error: push: no space left")
+    # . write-buffered(Stderr, "error: push: no space left")
+    # . . push args
+    68/push  "error: push: no space left"/imm32
+    68/push  Stderr/imm32
+    # . . call
+    e8/call  write-buffered/disp32
+    # . . discard args
+    81          0/subop/add         3/mod/direct    4/rm32/esp    .           .             .           .           .               8/imm32           # add to esp
+    # . flush(Stderr)
+    # . . push args
+    68/push  Stderr/imm32
+    # . . call
+    e8/call  flush/disp32
+    # . . discard args
+    81          0/subop/add         3/mod/direct    4/rm32/esp    .           .             .           .           .               4/imm32           # add to esp
+    # . syscall(exit, 1)
+    bb/copy-to-ebx  1/imm32
+    e8/call  syscall_exit/disp32
+    # never gets here
+
+test-push:
+    # . prologue
+    55/push-ebp
+    89/copy                         3/mod/direct    5/rm32/ebp    .           .             .           4/r32/esp   .               .                 # copy esp to ebp
+    # var stack/ecx = empty stack of size 8
+    68/push 0/imm32
+    68/push 0/imm32
+    68/push 8/imm32/size
+    68/push 0/imm32/top
+    89/copy                         3/mod/direct    1/rm32/ecx    .           .             .           4/r32/esp   .               .                 # copy esp to ecx
+    # push(stack, 0x42)
+    # . . push args
+    68/push  0x42/imm32
+    51/push-ecx
+    # . . call
+    e8/call  push/disp32
+    # . . discard args
+    81          0/subop/add         3/mod/direct    4/rm32/esp    .           .             .           .           .               8/imm32           # add to esp
+    # check top
+    58/pop-to-eax
+    # . check-ints-equal(eax, 4, msg)
+    # . . push args
+    68/push  "F - test-push: top"/imm32
+    68/push  4/imm32
+    50/push-eax
+    # . . call
+    e8/call  check-ints-equal/disp32
+    # . . discard args
+    81          0/subop/add         3/mod/direct    4/rm32/esp    .           .             .           .           .               0xc/imm32         # add to esp
+    # check size
+    58/pop-to-eax
+    # . check-ints-equal(eax, 8, msg)
+    # . . push args
+    68/push  "F - test-push: size"/imm32
+    68/push  8/imm32
+    50/push-eax
+    # . . call
+    e8/call  check-ints-equal/disp32
+    # . . discard args
+    81          0/subop/add         3/mod/direct    4/rm32/esp    .           .             .           .           .               0xc/imm32         # add to esp
+    # first word is 0x42
+    58/pop-to-eax
+    # . check-ints-equal(eax, 0x42, msg)
+    # . . push args
+    68/push  "F - test-push: data[0..3]"/imm32
+    68/push  0x42/imm32
+    50/push-eax
+    # . . call
+    e8/call  check-ints-equal/disp32
+    # . . discard args
+    81          0/subop/add         3/mod/direct    4/rm32/esp    .           .             .           .           .               0xc/imm32         # add to esp
+    # second word is 0
+    58/pop-to-eax
+    # . check-ints-equal(eax, 0, msg)
+    # . . push args
+    68/push  "F - test-push: data[4..7]"/imm32
+    68/push  0/imm32
+    50/push-eax
+    # . . call
+    e8/call  check-ints-equal/disp32
+    # . . discard args
+    81          0/subop/add         3/mod/direct    4/rm32/esp    .           .             .           .           .               0xc/imm32         # add to esp
+    # . epilogue
+    89/copy                         3/mod/direct    4/rm32/esp    .           .             .           5/r32/ebp   .               .                 # copy ebp to esp
+    5d/pop-to-ebp
+    c3/return
+
+# TODO: make this generic
+pop:  # s: (addr stack) -> n/eax: int
+    # . prologue
+    55/push-ebp
+    89/copy                         3/mod/direct    5/rm32/ebp    .           .             .           4/r32/esp   .               .                 # copy esp to ebp
+    # . save registers
+    51/push-ecx
+    56/push-esi
+    # esi = s
+    8b/copy                         1/mod/*+disp8   5/rm32/ebp    .           .             .           6/r32/esi   8/disp8         .                 # copy *(ebp+8) to esi
+    # if (s->top <= 0) abort
+    81          7/subop/compare     0/mod/indirect  6/rm32/esi    .           .             .           .           .               0/imm32           # compare *esi
+    7e/jump-if-<=  $pop:abort/disp8
+    # s->top -= 4
+    81          5/subop/subtract    0/mod/direct    6/rm32/esi    .           .             .           .           .               4/imm32           # subtract from *esi
+    # eax = s->data[s->top]
+    8b/copy                         0/mod/indirect  6/rm32/esi    .           .             .           1/r32/ecx   .               .                 # copy *esi to ecx
+    8b/copy                         1/mod/*+disp8   4/rm32/sib    6/base/esi  1/index/ecx   .           0/r32/eax   8/disp8         .                 # copy *(esi+ecx+8) to eax
+    # s->data[s->top] = 0
+    c7          0/subop/copy        1/mod/*+disp8   4/rm32/sib    6/base/esi  1/index/ecx   .           0/r32/eax   8/disp8         0/imm32           # copy to *(esi+ecx+8)
+$pop:end:
+    # . restore registers
+    5e/pop-to-esi
+    59/pop-to-ecx
+    # . epilogue
+    89/copy                         3/mod/direct    4/rm32/esp    .           .             .           5/r32/ebp   .               .                 # copy ebp to esp
+    5d/pop-to-ebp
+    c3/return
+
+$pop:abort:
+    # print(stderr, "error: pop: nothing left in stack")
+    # . write-buffered(Stderr, "error: pop: nothing left in stack")
+    # . . push args
+    68/push  "error: pop: nothing left in stack"/imm32
+    68/push  Stderr/imm32
+    # . . call
+    e8/call  write-buffered/disp32
+    # . . discard args
+    81          0/subop/add         3/mod/direct    4/rm32/esp    .           .             .           .           .               8/imm32           # add to esp
+    # . flush(Stderr)
+    # . . push args
+    68/push  Stderr/imm32
+    # . . call
+    e8/call  flush/disp32
+    # . . discard args
+    81          0/subop/add         3/mod/direct    4/rm32/esp    .           .             .           .           .               4/imm32           # add to esp
+    # . syscall(exit, 1)
+    bb/copy-to-ebx  1/imm32
+    e8/call  syscall_exit/disp32
+    # never gets here
+
+test-pop:
+    # . prologue
+    55/push-ebp
+    89/copy                         3/mod/direct    5/rm32/ebp    .           .             .           4/r32/esp   .               .                 # copy esp to ebp
+    # var stack/ecx = stack of size 8 containing just 0x42
+    68/push 0/imm32
+    68/push 0x42/imm32
+    68/push 8/imm32/size
+    68/push 4/imm32/top
+    89/copy                         3/mod/direct    1/rm32/ecx    .           .             .           4/r32/esp   .               .                 # copy esp to ecx
+    # eax = pop(stack)
+    # . . push args
+    51/push-ecx
+    # . . call
+    e8/call  pop/disp32
+    # . . discard args
+    81          0/subop/add         3/mod/direct    4/rm32/esp    .           .             .           .           .               4/imm32           # add to esp
+    # check-ints-equal(eax, 0x42, msg)
+    # . . push args
+    68/push  "F - test-pop: result"/imm32
+    68/push  0x42/imm32
+    50/push-eax
+    # . . call
+    e8/call  check-ints-equal/disp32
+    # . . discard args
+    81          0/subop/add         3/mod/direct    4/rm32/esp    .           .             .           .           .               0xc/imm32         # add to esp
+    # check top
+    58/pop-to-eax
+    # . check-ints-equal(eax, 0, msg)
+    # . . push args
+    68/push  "F - test-pop: top"/imm32
+    68/push  0/imm32
+    50/push-eax
+    # . . call
+    e8/call  check-ints-equal/disp32
+    # . . discard args
+    81          0/subop/add         3/mod/direct    4/rm32/esp    .           .             .           .           .               0xc/imm32         # add to esp
+    # check size
+    58/pop-to-eax
+    # . check-ints-equal(eax, 8, msg)
+    # . . push args
+    68/push  "F - test-pop: size"/imm32
+    68/push  8/imm32
+    50/push-eax
+    # . . call
+    e8/call  check-ints-equal/disp32
+    # . . discard args
+    81          0/subop/add         3/mod/direct    4/rm32/esp    .           .             .           .           .               0xc/imm32         # add to esp
+    # . epilogue
+    89/copy                         3/mod/direct    4/rm32/esp    .           .             .           5/r32/ebp   .               .                 # copy ebp to esp
+    5d/pop-to-ebp
+    c3/return
+
+# TODO: make this generic
+top:  # s: (addr stack) -> n/eax: int
+    # . prologue
+    55/push-ebp
+    89/copy                         3/mod/direct    5/rm32/ebp    .           .             .           4/r32/esp   .               .                 # copy esp to ebp
+    # . save registers
+    51/push-ecx
+    56/push-esi
+    # esi = s
+    8b/copy                         1/mod/*+disp8   5/rm32/ebp    .           .             .           6/r32/esi   8/disp8         .                 # copy *(ebp+8) to esi
+    # if (s->top <= 0) abort
+    81          7/subop/compare     0/mod/indirect  6/rm32/esi    .           .             .           .           .               0/imm32           # compare *esi
+    7e/jump-if-<=  $top:abort/disp8
+    # n = s->data[s->top - 4]
+    8b/copy                         0/mod/indirect  6/rm32/esi    .           .             .           1/r32/ecx   .               .                 # copy *esi to ecx
+    81          5/subop/subtract    3/mod/direct    1/rm32/ecx    .           .             .           .           .               4/imm32           # subtract from ecx
+    8b/copy                         1/mod/*+disp8   4/rm32/sib    6/base/esi  1/index/ecx   .           0/r32/eax   8/disp8         .                 # copy *(esi+ecx+8) to eax
+$top:end:
+    # . restore registers
+    5e/pop-to-esi
+    59/pop-to-ecx
+    # . epilogue
+    89/copy                         3/mod/direct    4/rm32/esp    .           .             .           5/r32/ebp   .               .                 # copy ebp to esp
+    5d/pop-to-ebp
+    c3/return
+
+$top:abort:
+    # print(stderr, "error: top: nothing left in stack")
+    # . write-buffered(Stderr, "error: top: nothing left in stack")
+    # . . push args
+    68/push  "error: top: nothing left in stack"/imm32
+    68/push  Stderr/imm32
+    # . . call
+    e8/call  write-buffered/disp32
+    # . . discard args
+    81          0/subop/add         3/mod/direct    4/rm32/esp    .           .             .           .           .               8/imm32           # add to esp
+    # . flush(Stderr)
+    # . . push args
+    68/push  Stderr/imm32
+    # . . call
+    e8/call  flush/disp32
+    # . . discard args
+    81          0/subop/add         3/mod/direct    4/rm32/esp    .           .             .           .           .               4/imm32           # add to esp
+    # . syscall(exit, 1)
+    bb/copy-to-ebx  1/imm32
+    e8/call  syscall_exit/disp32
+    # never gets here
+
+test-top:
+    # . prologue
+    55/push-ebp
+    89/copy                         3/mod/direct    5/rm32/ebp    .           .             .           4/r32/esp   .               .                 # copy esp to ebp
+    # var stack/ecx = stack of size 8 containing just 0x42
+    68/push  0/imm32
+    68/push  0x42/imm32
+    68/push  8/imm32/size
+    68/push  4/imm32/top
+    89/copy                         3/mod/direct    1/rm32/ecx    .           .             .           4/r32/esp   .               .                 # copy esp to ecx
+    # eax = top(stack)
+    # . . push args
+    51/push-ecx
+    # . . call
+    e8/call  top/disp32
+    # . . discard args
+    81          0/subop/add         3/mod/direct    4/rm32/esp    .           .             .           .           .               4/imm32           # add to esp
+    # check-ints-equal(eax, 42, msg")
+    # . . push args
+    68/push  "F - test-top: result"/imm32
+    68/push  0x42/imm32
+    50/push-eax
+    # . . call
+    e8/call  check-ints-equal/disp32
+    # . . discard args
+    81          0/subop/add         3/mod/direct    4/rm32/esp    .           .             .           .           .               0xc/imm32         # add to esp
+    # . epilogue
+    89/copy                         3/mod/direct    4/rm32/esp    .           .             .           5/r32/ebp   .               .                 # copy ebp to esp
+    5d/pop-to-ebp
+    c3/return
+
+# . . vim:nowrap:textwidth=0