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1 files changed, 0 insertions, 207 deletions

diff --git a/subx/068allocate.subx b/subx/068allocate.subx
deleted file mode 100644
index 37b01d21..00000000
--- a/subx/068allocate.subx
+++ /dev/null
@@ -1,207 +0,0 @@
-# Helper to dynamically allocate memory on the heap.
-#
-# We'd like to be able to write tests for functions that allocate memory,
-# making assertions on the precise addresses used. To achieve this we'll pass
-# in an *allocation descriptor* to allocate from.
-#
-# Allocation descriptors are also useful outside of tests. Assembly and machine
-# code are of necessity unsafe languages, and one of the most insidious kinds
-# of bugs unsafe languages expose us to are dangling pointers to memory that
-# has been freed and potentially even reused for something totally different.
-# To reduce the odds of such "use after free" errors, SubX programs tend to not
-# reclaim and reuse dynamically allocated memory. (Running out of memory is far
-# easier to debug.) Long-running programs that want to reuse memory are mostly
-# on their own to be careful. However, they do get one bit of help: they can
-# carve out chunks of memory and then allocate from them manually using this
-# very same 'allocate' helper. They just need a new allocation descriptor for
-# their book-keeping.
-
-== data
-
-# The 'global' allocation descriptor. Pass this into 'allocate' to claim a
-# hitherto unused bit of memory.
-Heap:
-    Start-of-heap/imm32  # curr
-    00 00 00 0b  # limit = 0x0b000000; keep sync'd with DATA_SEGMENT + SEGMENT_ALIGNMENT
-
-== 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
-
-# main:
-    e8/call  run-tests/disp32  # 'run-tests' is a function created automatically by SubX. It calls all functions that start with 'test-'.
-    # 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
-
-# Claim the next 'n' bytes of memory starting at ad->curr and update ad->curr.
-# If there isn't enough memory before ad->limit, return 0 and leave 'ad' unmodified.
-allocate:  # ad : (address allocation-descriptor), n : int -> address-or-null/EAX
-    # . prolog
-    55/push-EBP
-    89/copy                         3/mod/direct    5/rm32/EBP    .           .             .           4/r32/ESP   .               .                 # copy ESP to EBP
-    # . save registers
-    51/push-ECX
-    52/push-EDX
-    # ECX = ad
-    8b/copy                         1/mod/*+disp8   5/rm32/EBP    .           .             .           1/r32/ECX   8/disp8         .                 # copy *(EBP+8) to ECX
-    # save ad->curr
-    8b/copy                         0/mod/indirect  1/rm32/ECX    .           .             .           0/r32/EAX   .               .                 # copy *ECX to EAX
-    # check if there's enough space
-    # . EDX = ad->curr + n
-    89/copy                         3/mod/direct    2/rm32/EDX    .           .             .           0/r32/EAX   .               .                 # copy EAX to EDX
-    03/add                          1/mod/*+disp8   5/rm32/EBP    .           .             .           2/r32/EDX   0xc/disp8       .                 # add *(EBP+12) to EDX
-    3b/compare                      1/mod/*+disp8   1/rm32/ECX    .           .             .           2/r32/EDX   4/disp8         .                 # compare EDX with *(ECX+4)
-    7c/jump-if-lesser  $allocate:commit/disp8
-    # return null if not
-    b8/copy-to-EAX  0/imm32
-    eb/jump  $allocate:end/disp8
-$allocate:commit:
-    # update ad->curr
-    89/copy                         0/mod/indirect  1/rm32/ECX    .           .             .           2/r32/EDX   .               .                 # copy EDX to *ECX
-$allocate:end:
-    # . restore registers
-    5a/pop-to-EDX
-    59/pop-to-ECX
-    # . epilog
-    89/copy                         3/mod/direct    4/rm32/ESP    .           .             .           5/r32/EBP   .               .                 # copy EBP to ESP
-    5d/pop-to-EBP
-    c3/return
-
-test-allocate-success:
-    # . prolog
-    55/push-EBP
-    89/copy                         3/mod/direct    5/rm32/EBP    .           .             .           4/r32/ESP   .               .                 # copy ESP to EBP
-    # var ad/ECX : (address allocation-descriptor) = {11, 15}
-    68/push  0xf/imm32/limit
-    68/push  0xb/imm32/curr
-    89/copy                         3/mod/direct    1/rm32/ECX    .           .             .           4/r32/ESP   .               .                 # copy ESP to ECX
-    # EAX = allocate(ad, 3)
-    # . . push args
-    68/push  3/imm32
-    51/push-ECX
-    # . . call
-    e8/call  allocate/disp32
-    # . . discard args
-    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               8/imm32           # add to ESP
-    # check-ints-equal(EAX, 11, msg)
-    # . . push args
-    68/push  "F - test-allocate-success: returns current pointer of allocation descriptor"/imm32
-    68/push  0xb/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-ints-equal(ad->curr, 14, msg)
-    # . . push args
-    68/push  "F - test-allocate-success: updates allocation descriptor"/imm32
-    68/push  0xe/imm32
-    ff          6/subop/push        0/mod/indirect  1/rm32/ECX    .           .             .           .           .               .                 # push *ECX
-    # . . call
-    e8/call  check-ints-equal/disp32
-    # . . discard args
-    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               0xc/imm32         # add to ESP
-    # . epilog
-    89/copy                         3/mod/direct    4/rm32/ESP    .           .             .           5/r32/EBP   .               .                 # copy EBP to ESP
-    5d/pop-to-EBP
-    c3/return
-
-test-allocate-failure:
-    # . prolog
-    55/push-EBP
-    89/copy                         3/mod/direct    5/rm32/EBP    .           .             .           4/r32/ESP   .               .                 # copy ESP to EBP
-    # var ad/ECX : (address allocation-descriptor) = {11, 15}
-    68/push  0xf/imm32/limit
-    68/push  0xb/imm32/curr
-    89/copy                         3/mod/direct    1/rm32/ECX    .           .             .           4/r32/ESP   .               .                 # copy ESP to ECX
-    # EAX = allocate(ad, 6)
-    # . . push args
-    68/push  6/imm32
-    51/push-ECX
-    # . . call
-    e8/call  allocate/disp32
-    # . . discard args
-    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               8/imm32           # add to ESP
-    # check-ints-equal(EAX, 0, msg)
-    # . . push args
-    68/push  "F - test-allocate-failure: returns null"/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
-    # no change to ad->curr
-    # . check-ints-equal(ad->curr, 11)
-    # . . push args
-    68/push  "F - test-allocate-failure: updates allocation descriptor"/imm32
-    68/push  0xb/imm32
-    ff          6/subop/push        0/mod/indirect  1/rm32/ECX    .           .             .           .           .               .                 # push *ECX
-    # . . call
-    e8/call  check-ints-equal/disp32
-    # . . discard args
-    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               0xc/imm32         # add to ESP
-    # . epilog
-    89/copy                         3/mod/direct    4/rm32/ESP    .           .             .           5/r32/EBP   .               .                 # copy EBP to ESP
-    5d/pop-to-EBP
-    c3/return
-
-# helper: create a nested allocation descriptor (useful for tests)
-allocate-region:  # ad : (address allocation-descriptor), n : int -> new-ad : (address allocation-descriptor)
-    # . prolog
-    55/push-EBP
-    89/copy                         3/mod/direct    5/rm32/EBP    .           .             .           4/r32/ESP   .               .                 # copy ESP to EBP
-    # . save registers
-    51/push-ECX
-    # EAX = allocate(ad, n)
-    # . . push args
-    ff          6/subop/push        1/mod/*+disp8   5/rm32/EBP    .           .             .           .           0xc/disp8       .                 # push *(EBP+12)
-    ff          6/subop/push        1/mod/*+disp8   5/rm32/EBP    .           .             .           .           8/disp8         .                 # push *(EBP+8)
-    # . . call
-    e8/call  allocate/disp32
-    # . . discard args
-    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               8/imm32           # add to ESP
-    # if EAX == 0 abort
-    81          7/subop/compare     3/mod/direct    0/rm32/EAX    .           .             .           .           .               0/imm32           # compare EAX
-    74/jump-if-equal  $allocate-region:abort/disp8
-    # earmark 8 bytes at the start for a new allocation descriptor
-    # . *EAX = EAX + 8
-    89/copy                         3/mod/direct    1/rm32/ECX    .           .             .           0/r32/EAX   .               .                 # copy EAX to ECX
-    81          0/subop/add         3/mod/direct    1/rm32/ECX    .           .             .           .           .               8/imm32           # add to ECX
-    89/copy                         0/mod/indirect  0/rm32/EAX    .           .             .           1/r32/ECX   .               .                 # copy ECX to *EAX
-    # . *(EAX+4) = EAX + n
-    89/copy                         3/mod/direct    1/rm32/ECX    .           .             .           0/r32/EAX   .               .                 # copy EAX to ECX
-    03/add                          1/mod/*+disp8   5/rm32/EBP    .           .             .           1/r32/ECX   0xc/disp8       .                 # add *(EBP+12) to ECX
-    89/copy                         1/mod/*+disp8   0/rm32/EAX    .           .             .           1/r32/ECX   4/disp8         .                 # copy ECX to *(EAX+4)
-    # . restore registers
-    59/pop-to-ECX
-    # . epilog
-    89/copy                         3/mod/direct    4/rm32/ESP    .           .             .           5/r32/EBP   .               .                 # copy EBP to ESP
-    5d/pop-to-EBP
-    c3/return
-
-# We could create a more general '$abort' jump target, but then we'd need to do
-# a conditional jump followed by loading the error message and an unconditional
-# jump. Or we'd need to unconditionally load the error message before a
-# conditional jump, even if it's unused the vast majority of the time. This way
-# we bloat a potentially cold segment in RAM so we can abort with a single
-# instruction.
-$allocate-region:abort:
-    # . _write(2/stderr, error)
-    # . . push args
-    68/push  "allocate-region: failed to allocate"/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
-    # . syscall(exit, 1)
-    bb/copy-to-EBX  1/imm32
-    b8/copy-to-EAX  1/imm32/exit
-    cd/syscall  0x80/imm8
-    # never gets here
-
-# . . vim:nowrap:textwidth=0