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| author | Kartik Agaram <vc@akkartik.com> | 2020-07-05 12:13:28 -0700 |
|---|---|---|
| committer | Kartik Agaram <vc@akkartik.com> | 2020-07-05 12:13:28 -0700 |
| commit | c09c91e185aad8e01b570c2569e13c1e429d2f99 (patch) | |
| tree | 52a5ae1494ad5b7b2319411815dc45510e761c24 /069allocate.subx | |
| parent | f2c5b05374186f9422cfdaf1ada096e39ac91a8b (diff) | |
| download | mu-c09c91e185aad8e01b570c2569e13c1e429d2f99.tar.gz | |
6612 - reorganize layers
Diffstat (limited to '069allocate.subx')
| -rw-r--r-- | 069allocate.subx | 953 |
1 files changed, 0 insertions, 953 deletions
diff --git a/069allocate.subx b/069allocate.subx deleted file mode 100644 index 4778b3ed..00000000 --- a/069allocate.subx +++ /dev/null @@ -1,953 +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 - -# Allocations are returned in a handle, which consists of an alloc-id and a payload. -# The alloc-id helps detect use-after-free errors. -Handle-size: # (addr int) - 8/imm32 - -# A default allocation descriptor for programs to use. -Heap: # allocation-descriptor - # curr - 0/imm32 - # limit - 0/imm32 - -# a reasonable default -Heap-size: # int - 0x600000/imm32/6MB - -Next-alloc-id: # int - 0x100/imm32 # save a few alloc ids for fake handles - -== 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 - -# Let's start initializing the default allocation descriptor. - -Entry: - # initialize heap - # . Heap = new-segment(Heap-size) - # . . push args - 68/push Heap/imm32 - ff 6/subop/push 0/mod/indirect 5/rm32/.disp32 . . . Heap-size/disp32 # push *Heap-size - # . . call - e8/call new-segment/disp32 - # . . discard args - 81 0/subop/add 3/mod/direct 4/rm32/esp . . . . . 8/imm32 # add to esp - - e8/call run-tests/disp32 # 'run-tests' is a function created automatically by SubX. It calls all functions that start with 'test-'. -$array-equal-main:end: - # syscall(exit, Num-test-failures) - 8b/copy 0/mod/indirect 5/rm32/.disp32 . . 3/r32/ebx Num-test-failures/disp32 # copy *Num-test-failures to ebx - e8/call syscall_exit/disp32 - -# Allocate and clear 'n' bytes of memory from an allocation-descriptor 'ad'. -# Abort if there isn't enough memory in 'ad'. -allocate: # ad: (addr allocation-descriptor), n: int, out: (addr handle) - # . prologue - 55/push-ebp - 89/copy 3/mod/direct 5/rm32/ebp . . . 4/r32/esp . . # copy esp to ebp - # . save registers - 50/push-eax - # allocate-raw(ad, n, out) - # . . push args - ff 6/subop/push 1/mod/*+disp8 5/rm32/ebp . . . . 0x10/disp8 . # push *(ebp+16) - ff 6/subop/push 1/mod/*+disp8 5/rm32/ebp . . . . 0xc/disp8 . # push *(ebp+12) - ff 6/subop/push 1/mod/*+disp8 5/rm32/ebp . . . . 8/disp8 . # push *(ebp+8) - # . . call - e8/call allocate-raw/disp32 - # . . discard args - 81 0/subop/add 3/mod/direct 4/rm32/esp . . . . . 0xc/imm32 # add to esp - # eax = out->payload + 4 - 8b/copy 1/mod/*+disp8 5/rm32/ebp . . . 0/r32/eax 0x10/disp8 . # copy *(ebp+16) to eax - 8b/copy 1/mod/*+disp8 0/rm32/eax . . . 0/r32/eax 4/disp8 . # copy *(eax+4) to eax - 05/add-to-eax 4/imm32 - # zero-out(eax, n) - # . . push args - ff 6/subop/push 1/mod/*+disp8 5/rm32/ebp . . . . 0xc/disp8 . # push *(ebp+12) - 50/push-eax - # . . call - e8/call zero-out/disp32 - # . . discard args - 81 0/subop/add 3/mod/direct 4/rm32/esp . . . . . 8/imm32 # add to esp -$allocate:end: - # . restore registers - 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 - -# Claim the next 'n' bytes of memory starting at ad->curr and update ad->curr. -# Abort if there isn't enough memory in 'ad'. -allocate-raw: # ad: (addr allocation-descriptor), n: int, out: (addr handle) - # . 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 - 52/push-edx - 53/push-ebx - 56/push-esi - 57/push-edi - # ecx = ad - 8b/copy 1/mod/*+disp8 5/rm32/ebp . . . 1/r32/ecx 8/disp8 . # copy *(ebp+8) to ecx - # edx = out - 8b/copy 1/mod/*+disp8 5/rm32/ebp . . . 2/r32/edx 0x10/disp8 . # copy *(ebp+16) to edx - # ebx = n - 8b/copy 1/mod/*+disp8 5/rm32/ebp . . . 3/r32/ebx 0xc/disp8 . # copy *(ebp+12) to ebx - # out->alloc-id = Next-alloc-id - 8b/copy 0/mod/indirect 5/rm32/.disp32 . . 0/r32/eax Next-alloc-id/disp32 # copy *Next-alloc-id to eax - 89/copy 0/mod/indirect 2/rm32/edx . . . 0/r32/eax . . # copy eax to *edx - # out->payload = ad->curr - 8b/copy 0/mod/indirect 1/rm32/ecx . . . 0/r32/eax . . # copy *ecx to eax -$allocate-raw:save-payload-in-eax: - 89/copy 1/mod/*+disp8 2/rm32/edx . . . 0/r32/eax 4/disp8 . # copy eax to *(edx+4) - # *out->payload = Next-alloc-id - 8b/copy 1/mod/*+disp8 2/rm32/edx . . . 7/r32/edi 4/disp8 . # copy *(edx+4) to edi - 8b/copy 0/mod/indirect 5/rm32/.disp32 . . 6/r32/esi Next-alloc-id/disp32 # copy *Next-alloc-id to esi - 89/copy 0/mod/indirect 7/rm32/edi . . . 6/r32/esi . . # copy esi to *edi -$allocate-raw:increment-next-alloc-id: - # increment *Next-alloc-id - ff 0/subop/increment 0/mod/indirect 5/rm32/.disp32 . . . Next-alloc-id/disp32 # increment *Next-alloc-id - # check if there's enough space - # TODO: move this check up before any state updates when we support error recovery - 8d/copy-address 1/mod/*+disp8 4/rm32/sib 0/base/eax 3/index/ebx . 0/r32/eax 4/disp8 . # copy eax+ebx+4 to eax - 3b/compare 1/mod/*+disp8 1/rm32/ecx . . . 0/r32/eax 4/disp8 . # compare eax with *(ecx+4) - 73/jump-if->=-signed $allocate-raw:abort/disp8 -$allocate-raw:commit: - # ad->curr += n+4 - 89/copy 0/mod/indirect 1/rm32/ecx . . . 0/r32/eax . . # copy eax to *ecx -$allocate-raw:end: - # . restore registers - 5f/pop-to-edi - 5e/pop-to-esi - 5b/pop-to-ebx - 5a/pop-to-edx - 59/pop-to-ecx - 58/pop-to-eax - # . epilogue - 89/copy 3/mod/direct 4/rm32/esp . . . 5/r32/ebp . . # copy ebp to esp - 5d/pop-to-ebp - c3/return - -$allocate-raw:abort: - # . _write(2/stderr, error) - # . . push args - 68/push "allocate: failed\n"/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 - e8/call syscall_exit/disp32 - # never gets here - -test-allocate-raw-success: - # . prologue - 55/push-ebp - 89/copy 3/mod/direct 5/rm32/ebp . . . 4/r32/esp . . # copy esp to ebp - # var ad/ecx: allocation-descriptor - 68/push 0/imm32/limit - 68/push 0/imm32/curr - 89/copy 3/mod/direct 1/rm32/ecx . . . 4/r32/esp . . # copy esp to ecx - # ad = new-segment(512) - # . . push args - 51/push-ecx - 68/push 0x200/imm32 - # . . call - e8/call new-segment/disp32 - # . . discard args - 81 0/subop/add 3/mod/direct 4/rm32/esp . . . . . 8/imm32 # add to esp - # var expected-payload/ebx = ad->curr - 8b/copy 0/mod/indirect 1/rm32/ecx . . . 3/r32/ebx . . # copy *ecx to ebx - # var h/edx: handle = {0, 0} - 68/push 0/imm32 - 68/push 0/imm32 - 89/copy 3/mod/direct 2/rm32/edx . . . 4/r32/esp . . # copy esp to edx - # *Next-alloc-id = 0x34 - c7 0/subop/copy 0/mod/indirect 5/rm32/.disp32 . . . Next-alloc-id/disp32 0x34/imm32 # copy to *Next-alloc-id - # allocate-raw(ad, 3, h) - # . . push args - 52/push-edx - 68/push 3/imm32 - 51/push-ecx - # . . call - e8/call allocate-raw/disp32 - # . . discard args - 81 0/subop/add 3/mod/direct 4/rm32/esp . . . . . 0xc/imm32 # add to esp - # check-ints-equal(h->alloc-id, 0x34, msg) - # . . push args - 68/push "F - test-allocate-raw-success: sets alloc-id in handle"/imm32 - 68/push 0x34/imm32 - ff 6/subop/push 0/mod/indirect 2/rm32/edx . . . . . . # push *edx - # . . 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(h->payload, expected-payload, msg) - # . . push args - 68/push "F - test-allocate-raw-success: sets payload in handle"/imm32 - 53/push-ebx - ff 6/subop/push 1/mod/*+disp8 2/rm32/edx . . . . 4/disp8 . # push *(edx+4) - # . . 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(h->payload->alloc-id, 0x34, msg) - # . . push args - 68/push "F - test-allocate-raw-success: sets alloc-id in payload"/imm32 - 68/push 0x34/imm32 - ff 6/subop/push 0/mod/indirect 3/rm32/ebx . . . . . . # push *ebx - # . . 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(*Next-alloc-id, 0x35, msg) - # . . push args - 68/push "F - test-allocate-raw-success: increments Next-alloc-id"/imm32 - 68/push 0x35/imm32 - ff 6/subop/push 0/mod/indirect 5/rm32/.disp32 . . . Next-alloc-id/disp32 # push *Next-alloc-id - # . . 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 - expected-payload, 3 + 4 for alloc-id, msg) - # . . push args - 68/push "F - test-allocate-raw-success: updates allocation descriptor"/imm32 - 68/push 7/imm32 - 8b/copy 0/mod/indirect 1/rm32/ecx . . . 0/r32/eax . . # copy *ecx to eax - 29/subtract 3/mod/direct 0/rm32/eax . . . 3/r32/ebx . . # subtract ebx from eax - 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 - # clean up - c7 0/subop/copy 0/mod/indirect 5/rm32/.disp32 . . . Next-alloc-id/disp32 0x100/imm32 # copy to *Next-alloc-id - # . epilogue - 89/copy 3/mod/direct 4/rm32/esp . . . 5/r32/ebp . . # copy ebp to esp - 5d/pop-to-ebp - c3/return - -lookup: # h: (handle T) -> eax: (addr T) - # . prologue - 55/push-ebp - 89/copy 3/mod/direct 5/rm32/ebp . . . 4/r32/esp . . # copy esp to ebp - # . save registers - 51/push-ecx - # eax = 0 - 31/xor 3/mod/direct 0/rm32/eax . . . 0/r32/eax . . # clear eax - # ecx = handle->alloc_id - 8b/copy 1/mod/*+disp8 5/rm32/ebp . . . 1/r32/ecx 8/disp8 . # copy *(ebp+8) to ecx - # if (ecx == 0) return 0 - 81 7/subop/compare 3/mod/direct 1/rm32/ecx . . . . . 0/imm32 # compare ecx - 74/jump-if-= $lookup:end/disp8 - # eax = handle->address (payload) - 8b/copy 1/mod/*+disp8 5/rm32/ebp . . . 0/r32/eax 0xc/disp8 . # copy *(ebp+12) to eax - # if (ecx != *eax) abort - 39/compare 0/mod/indirect 0/rm32/eax . . . 1/r32/ecx . . # compare *eax and ecx - 75/jump-if-!= $lookup:abort/disp8 - # add 4 to eax - 05/add-to-eax 4/imm32 -$lookup:end: - # . restore registers - 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 - -$lookup:abort: - # . _write(2/stderr, msg) - # . . push args - 68/push "lookup failed\n"/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/exit-status - e8/call syscall_exit/disp32 - -test-lookup-success: - # . prologue - 55/push-ebp - 89/copy 3/mod/direct 5/rm32/ebp . . . 4/r32/esp . . # copy esp to ebp - # var ad/ebx: allocation-descriptor - 68/push 0/imm32/limit - 68/push 0/imm32/curr - 89/copy 3/mod/direct 3/rm32/ebx . . . 4/r32/esp . . # copy esp to ebx - # ad = new-segment(512) - # . . push args - 53/push-ebx - 68/push 0x200/imm32 - # . . call - e8/call new-segment/disp32 - # . . discard args - 81 0/subop/add 3/mod/direct 4/rm32/esp . . . . . 8/imm32 # add to esp - # var handle/ecx: handle - 68/push 0/imm32/address - 68/push 0/imm32/alloc-id - 89/copy 3/mod/direct 1/rm32/ecx . . . 4/r32/esp . . # copy esp to ecx - # var old-top/edx = ad->curr - 8b/copy 0/mod/indirect 3/rm32/ebx . . . 2/r32/edx . . # copy *ebx to edx - # allocate-raw(ad, 2, handle) - # . . push args - 51/push-ecx - 68/push 2/imm32/size - 53/push-ebx - # . . call - e8/call allocate-raw/disp32 - # . . discard args - 81 0/subop/add 3/mod/direct 4/rm32/esp . . . . . 0xc/imm32 # add to esp - # eax = lookup(handle) - # . . push args - ff 6/subop/push 1/mod/*+disp8 1/rm32/ecx . . . . 4/disp8 . # push *(ecx+4) - ff 6/subop/push 0/mod/indirect 1/rm32/ecx . . . . . . # push *ecx - # . . call - e8/call lookup/disp32 - # . . discard args - 81 0/subop/add 3/mod/direct 4/rm32/esp . . . . . 8/imm32 # add to esp - # eax contains old top of heap, except skipping the alloc-id in the payload - # . check-ints-equal(eax, old-top+4, msg) - # . . push args - 68/push "F - test-lookup-success"/imm32 - 81 0/subop/add 3/mod/direct 2/rm32/edx . . . . . 4/imm32 # add to edx - 52/push-edx - 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 - # clean up - c7 0/subop/copy 0/mod/indirect 5/rm32/.disp32 . . . Next-alloc-id/disp32 0x100/imm32 # copy to *Next-alloc-id - # . epilogue - 89/copy 3/mod/direct 4/rm32/esp . . . 5/r32/ebp . . # copy ebp to esp - 5d/pop-to-ebp - c3/return - -test-lookup-null-returns-null: - # . prologue - 55/push-ebp - 89/copy 3/mod/direct 5/rm32/ebp . . . 4/r32/esp . . # copy esp to ebp - # var handle/ecx: handle - 68/push 0/imm32/address - 68/push 0/imm32/alloc-id - 89/copy 3/mod/direct 1/rm32/ecx . . . 4/r32/esp . . # copy esp to ecx - # eax = lookup(handle) - # . . push args - ff 6/subop/push 1/mod/*+disp8 1/rm32/ecx . . . . 4/disp8 . # push *(ecx+4) - ff 6/subop/push 0/mod/indirect 1/rm32/ecx . . . . . . # push *ecx - # . . call - e8/call lookup/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-lookup-null-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 - # . epilogue - 89/copy 3/mod/direct 4/rm32/esp . . . 5/r32/ebp . . # copy ebp to esp - 5d/pop-to-ebp - c3/return - -_pending-test-lookup-failure: - # . prologue - 55/push-ebp - 89/copy 3/mod/direct 5/rm32/ebp . . . 4/r32/esp . . # copy esp to ebp - # var heap/esi: allocation-descriptor - 68/push 0/imm32/limit - 68/push 0/imm32/curr - 89/copy 3/mod/direct 6/rm32/esi . . . 4/r32/esp . . # copy esp to esi - # heap = new-segment(512) - # . . push args - 56/push-esi - 68/push 0x200/imm32 - # . . call - e8/call new-segment/disp32 - # . . discard args - 81 0/subop/add 3/mod/direct 4/rm32/esp . . . . . 8/imm32 # add to esp - # var h1/ecx: handle - 68/push 0/imm32/address - 68/push 0/imm32/alloc-id - 89/copy 3/mod/direct 1/rm32/ecx . . . 4/r32/esp . . # copy esp to ecx - # var old_top/ebx = heap->curr - 8b/copy 0/mod/indirect 6/rm32/esi . . . 3/r32/ebx . . # copy *esi to ebx - # first allocation, to h1 - # . allocate(heap, 2, h1) - # . . push args - 51/push-ecx - 68/push 2/imm32/size - 56/push-esi - # . . call - e8/call allocate/disp32 - # . . discard args - 81 0/subop/add 3/mod/direct 4/rm32/esp . . . . . 0xc/imm32 # add to esp - # reset heap->curr to mimic reclamation - 89/copy 0/mod/indirect 6/rm32/esi . . . 3/r32/ebx . . # copy ebx to *esi - # second allocation that returns the same address as the first - # var h2/edx: handle - 68/push 0/imm32/address - 68/push 0/imm32/alloc-id - 89/copy 3/mod/direct 2/rm32/edx . . . 4/r32/esp . . # copy esp to edx - # . allocate(heap, 2, h2) - # . . push args - 52/push-edx - 68/push 2/imm32/size - 56/push-esi - # . . call - e8/call allocate/disp32 - # . . discard args - 81 0/subop/add 3/mod/direct 4/rm32/esp . . . . . 0xc/imm32 # add to esp - # check-ints-equal(h1->address, h2->address, msg) - # . . push args - 68/push "F - test-lookup-failure"/imm32 - ff 6/subop/push 1/mod/*+disp8 2/rm32/ecx . . . . 4/disp8 . # push *(edx+4) - ff 6/subop/push 1/mod/*+disp8 1/rm32/ecx . . . . 4/disp8 . # push *(ecx+4) - # . . call - e8/call check-ints-equal/disp32 - # . . discard args - 81 0/subop/add 3/mod/direct 4/rm32/esp . . . . . 0xc/imm32 # add to esp - # lookup(h1) should crash - # . . push args - ff 6/subop/push 1/mod/*+disp8 1/rm32/ecx . . . . 4/disp8 . # push *(ecx+4) - ff 6/subop/push 0/mod/indirect 1/rm32/ecx . . . . . . # push *ecx - # . . call - e8/call lookup/disp32 - # should never get past this point - # . . discard args - 81 0/subop/add 3/mod/direct 4/rm32/esp . . . . . 8/imm32 # add to esp - # clean up - c7 0/subop/copy 0/mod/indirect 5/rm32/.disp32 . . . Next-alloc-id/disp32 0x100/imm32 # copy to *Next-alloc-id - # . epilogue - 89/copy 3/mod/direct 4/rm32/esp . . . 5/r32/ebp . . # copy ebp to esp - 5d/pop-to-ebp - c3/return - -# when comparing handles, just treat them as pure values -handle-equal?: # a: handle, b: handle -> eax: boolean - # . prologue - 55/push-ebp - 89/copy 3/mod/direct 5/rm32/ebp . . . 4/r32/esp . . # copy esp to ebp - # . save registers - 51/push-ecx - # eax = false - b8/copy-to-eax 0/imm32/false -$handle-equal?:compare-alloc-id: - # ecx = a->alloc_id - 8b/copy 1/mod/*+disp8 5/rm32/ebp . . . 1/r32/ecx 8/disp8 . # copy *(ebp+8) to ecx - # if (ecx != b->alloc_id) return false - 39/compare 1/mod/*+disp8 5/rm32/ebp . . . 1/r32/ecx 0x10/disp8 . # compare ecx and *(ebp+16) - 75/jump-if-!= $handle-equal?:end/disp8 -$handle-equal?:compare-address: - # ecx = handle->address - 8b/copy 1/mod/*+disp8 5/rm32/ebp . . . 1/r32/ecx 0xc/disp8 . # copy *(ebp+12) to ecx - # if (ecx != b->address) return false - 39/compare 1/mod/*+disp8 5/rm32/ebp . . . 1/r32/ecx 0x14/disp8 . # compare ecx and *(ebp+20) - 75/jump-if-!= $handle-equal?:end/disp8 -$handle-equal?:return-true: - # return true - b8/copy-to-eax 1/imm32/true -$handle-equal?:end: - # . restore registers - 59/pop-to-ecx - # . epilogue - 89/copy 3/mod/direct 4/rm32/esp . . . 5/r32/ebp . . # copy ebp to esp - 5d/pop-to-ebp - c3/return - -copy-handle: # src: handle, dest: (addr handle) - # . prologue - 55/push-ebp - 89/copy 3/mod/direct 5/rm32/ebp . . . 4/r32/esp . . # copy esp to ebp - # . save registers - 50/push-eax - 51/push-ecx - # ecx = dest - 8b/copy 1/mod/*+disp8 5/rm32/ebp . . . 1/r32/ecx 0x10/disp8 . # copy *(ebp+16) to ecx - # *dest = src - 8b/copy 1/mod/*+disp8 5/rm32/ebp . . . 0/r32/eax 8/disp8 . # copy *(ebp+8) to eax - 89/copy 0/mod/indirect 1/rm32/ecx . . . 0/r32/eax . . # copy eax to *ecx - 8b/copy 1/mod/*+disp8 5/rm32/ebp . . . 0/r32/eax 0xc/disp8 . # copy *(ebp+12) to eax - 89/copy 1/mod/*+disp8 1/rm32/ecx . . . 0/r32/eax 4/disp8 . # copy eax to *(ecx+4) -$copy-handle: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 - -# helper: create a nested allocation descriptor (useful for tests) -allocate-region: # ad: (addr allocation-descriptor), n: int, out: (addr handle allocation-descriptor) - # . 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 - # allocate(ad, n, out) - # . . push args - ff 6/subop/push 1/mod/*+disp8 5/rm32/ebp . . . . 0x10/disp8 . # push *(ebp+16) - 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 . . . . . 0xc/imm32 # add to esp - # eax = out->payload - 8b/copy 1/mod/*+disp8 5/rm32/ebp . . . 0/r32/eax 0x10/disp8 . # copy *(ebp+16) to eax - 8b/copy 1/mod/*+disp8 0/rm32/eax . . . 0/r32/eax 4/disp8 . # copy *(eax+4) to eax - # skip payload->allocid - 05/add-to-eax 4/imm32 - # if (eax == 0) abort - 3d/compare-eax-and 0/imm32 - 74/jump-if-= $allocate-region:abort/disp8 - # earmark 8 bytes at the start for a new allocation descriptor - # . *eax = eax + 8 - 89/copy 3/mod/direct 1/rm32/ecx . . . 0/r32/eax . . # copy eax to ecx - 81 0/subop/add 3/mod/direct 1/rm32/ecx . . . . . 8/imm32 # add to ecx - 89/copy 0/mod/indirect 0/rm32/eax . . . 1/r32/ecx . . # copy ecx to *eax - # . *(eax+4) = eax + n - 89/copy 3/mod/direct 1/rm32/ecx . . . 0/r32/eax . . # copy eax to ecx - 03/add 1/mod/*+disp8 5/rm32/ebp . . . 1/r32/ecx 0xc/disp8 . # add *(ebp+12) to ecx - 89/copy 1/mod/*+disp8 0/rm32/eax . . . 1/r32/ecx 4/disp8 . # copy ecx to *(eax+4) - # . restore registers - 59/pop-to-ecx - 58/pop-to-eax - # . epilogue - 89/copy 3/mod/direct 4/rm32/esp . . . 5/r32/ebp . . # copy ebp to esp - 5d/pop-to-ebp - c3/return - -# We could create a more general '$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. -$allocate-region:abort: - # . _write(2/stderr, error) - # . . push args - 68/push "allocate-region: failed to allocate\n"/imm32 - 68/push 2/imm32/stderr - # . . call - e8/call _write/disp32 - # . . discard args - 81 0/subop/add 3/mod/direct 4/rm32/esp . . . . . 8/imm32 # add to esp - # . syscall(exit, 1) - bb/copy-to-ebx 1/imm32 - e8/call syscall_exit/disp32 - # never gets here - -# Claim the next 'n+4' bytes of memory and initialize the first 4 to n. -# Abort if there isn't enough memory in 'ad'. -allocate-array: # ad: (addr allocation-descriptor), n: int, out: (addr handle) - # . prologue - 55/push-ebp - 89/copy 3/mod/direct 5/rm32/ebp . . . 4/r32/esp . . # copy esp to ebp - # . save registers - 50/push-eax - 51/push-ecx - 52/push-edx - # ecx = n - 8b/copy 1/mod/*+disp8 5/rm32/ebp . . . 1/r32/ecx 0xc/disp8 . # copy *(ebp+12) to ecx - # var size/edx: int = n+4 - 8d/copy-address 1/mod/*+disp8 1/rm32/ecx . . . 2/r32/edx 4/disp8 . # copy ecx+4 to edx - # allocate(ad, size, out) - # . . push args - ff 6/subop/push 1/mod/*+disp8 5/rm32/ebp . . . . 0x10/disp8 . # push *(ebp+16) - 52/push-edx - ff 6/subop/push 1/mod/*+disp8 5/rm32/ebp . . . . 8/disp8 . # push *(ebp+8) - # . . call - e8/call allocate/disp32 - # . . discard args - 81 0/subop/add 3/mod/direct 4/rm32/esp . . . . . 0xc/imm32 # add to esp - # *out->payload = n - 8b/copy 1/mod/*+disp8 5/rm32/ebp . . . 0/r32/eax 0x10/disp8 . # copy *(ebp+16) to eax - 8b/copy 1/mod/*+disp8 0/rm32/eax . . . 0/r32/eax 4/disp8 . # copy *(eax+4) to eax - # . skip payload->allocid - 05/add-to-eax 4/imm32 - # . - 89/copy 0/mod/indirect 0/rm32/eax . . . 1/r32/ecx . . # copy ecx to *eax -$allocate-array:end: - # . restore registers - 5a/pop-to-edx - 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-allocate-array: - # . prologue - 55/push-ebp - 89/copy 3/mod/direct 5/rm32/ebp . . . 4/r32/esp . . # copy esp to ebp - # var ad/ecx: allocation-descriptor - 68/push 0/imm32/limit - 68/push 0/imm32/curr - 89/copy 3/mod/direct 1/rm32/ecx . . . 4/r32/esp . . # copy esp to ecx - # ad = new-segment(512) - # . . push args - 51/push-ecx - 68/push 0x200/imm32 - # . . call - e8/call new-segment/disp32 - # . . discard args - 81 0/subop/add 3/mod/direct 4/rm32/esp . . . . . 8/imm32 # add to esp - # var expected-payload/ebx = ad->curr - 8b/copy 0/mod/indirect 1/rm32/ecx . . . 3/r32/ebx . . # copy *ecx to ebx - # var h/edx: handle = {0, 0} - 68/push 0/imm32 - 68/push 0/imm32 - 89/copy 3/mod/direct 2/rm32/edx . . . 4/r32/esp . . # copy esp to edx - # *Next-alloc-id = 0x34 - c7 0/subop/copy 0/mod/indirect 5/rm32/.disp32 . . . Next-alloc-id/disp32 0x34/imm32 # copy to *Next-alloc-id - # allocate-array(ad, 3, h) - # . . push args - 52/push-edx - 68/push 3/imm32 - 51/push-ecx - # . . call - e8/call allocate-array/disp32 - # . . discard args - 81 0/subop/add 3/mod/direct 4/rm32/esp . . . . . 0xc/imm32 # add to esp - # check-ints-equal(h->alloc-id, 0x34, msg) - # . . push args - 68/push "F - test-allocate-array: sets alloc-id in handle"/imm32 - 68/push 0x34/imm32 - ff 6/subop/push 0/mod/indirect 2/rm32/edx . . . . . . # push *edx - # . . 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(h->payload, expected-payload, msg) - # . . push args - 68/push "F - test-allocate-array: sets payload in handle"/imm32 - 53/push-ebx - ff 6/subop/push 1/mod/*+disp8 2/rm32/edx . . . . 4/disp8 . # push *(edx+4) - # . . 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(h->payload->alloc-id, 0x34, msg) - # . . push args - 68/push "F - test-allocate-array: sets alloc-id in payload"/imm32 - 68/push 0x34/imm32 - ff 6/subop/push 0/mod/indirect 3/rm32/ebx . . . . . . # push *ebx - # . . 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(h->payload->size, 3, msg) - # . . push args - 68/push "F - test-allocate-array: sets array size in payload"/imm32 - 68/push 3/imm32 - ff 6/subop/push 1/mod/*+disp8 3/rm32/ebx . . . . 4/disp8 . # push *(ebx+4) - # . . 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(*Next-alloc-id, 0x35, msg) - # . . push args - 68/push "F - test-allocate-array: increments Next-alloc-id"/imm32 - 68/push 0x35/imm32 - ff 6/subop/push 0/mod/indirect 5/rm32/.disp32 . . . Next-alloc-id/disp32 # push *Next-alloc-id - # . . 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 - expected-payload, 3 + 4 for alloc-id + 4 for array size, msg) - # . . push args - 68/push "F - test-allocate-array: updates allocation descriptor"/imm32 - 68/push 0xb/imm32 - 8b/copy 0/mod/indirect 1/rm32/ecx . . . 0/r32/eax . . # copy *ecx to eax - 29/subtract 3/mod/direct 0/rm32/eax . . . 3/r32/ebx . . # subtract ebx from eax - 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 - # clean up - c7 0/subop/copy 0/mod/indirect 5/rm32/.disp32 . . . Next-alloc-id/disp32 1/imm32 # copy to *Next-alloc-id - # . epilogue - 89/copy 3/mod/direct 4/rm32/esp . . . 5/r32/ebp . . # copy ebp to esp - 5d/pop-to-ebp - c3/return - -copy-array: # ad: (addr allocation-descriptor), src: (addr array), out: (addr handle) - # . 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 - 52/push-edx - 56/push-esi - # esi = src - 8b/copy 1/mod/*+disp8 5/rm32/ebp . . . 6/r32/esi 0xc/disp8 . # copy *(ebp+12) to esi - # var size/ecx: int = src->size+4 - 8b/copy 0/mod/indirect 6/rm32/esi . . . 1/r32/ecx . . # copy *esi to ecx - 81 0/subop/add 3/mod/direct 1/rm32/ecx . . . . . 4/imm32 # add to ecx - # allocate(ad, size, out) - # . . push args - ff 6/subop/push 1/mod/*+disp8 5/rm32/ebp . . . . 0x10/disp8 . # push *(ebp+16) - 51/push-ecx - 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 . . . . . 0xc/imm32 # add to esp - # var payload/eax: (addr byte) = out->payload - 8b/copy 1/mod/*+disp8 5/rm32/ebp . . . 0/r32/eax 0x10/disp8 . # copy *(ebp+16) to eax - 8b/copy 1/mod/*+disp8 0/rm32/eax . . . 0/r32/eax 4/disp8 . # copy *(eax+4) to eax - # . skip payload->allocid - 05/add-to-eax 4/imm32 - # var max/ecx: (addr byte) = payload + size - 01/add 3/mod/direct 1/rm32/ecx . . . 0/r32/eax . . # add eax to ecx - # _append-4(payload, max, src, &src->data[src->size]) - # . . push &src->data[src->size] - 8b/copy 0/mod/indirect 6/rm32/esi . . . 2/r32/edx . . # copy *esi to edx - 8d/copy-address 1/mod/*+disp8 4/rm32/sib 6/base/esi 2/index/edx . 2/r32/edx 4/disp8 . # copy esi+edx+4 to edx - 52/push-edx - # . . push src - 56/push-esi - # . . push max - 51/push-ecx - # . . push payload - 50/push-eax - # . . call - e8/call _append-4/disp32 - # . . discard args - 81 0/subop/add 3/mod/direct 4/rm32/esp . . . . . 0x10/imm32 # add to esp -$copy-array:end: - # . restore registers - 5e/pop-to-esi - 5a/pop-to-edx - 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-copy-array: - # . prologue - 55/push-ebp - 89/copy 3/mod/direct 5/rm32/ebp . . . 4/r32/esp . . # copy esp to ebp - # var src/esi: (addr array int) = [3, 4, 5] - 68/push 5/imm32 - 68/push 4/imm32 - 68/push 3/imm32 - 68/push 0xc/imm32/size - 89/copy 3/mod/direct 6/rm32/esi . . . 4/r32/esp . . # copy esp to esi - # var ad/ecx: allocation-descriptor - 68/push 0/imm32/limit - 68/push 0/imm32/curr - 89/copy 3/mod/direct 1/rm32/ecx . . . 4/r32/esp . . # copy esp to ecx - # ad = new-segment(512) - # . . push args - 51/push-ecx - 68/push 0x200/imm32 - # . . call - e8/call new-segment/disp32 - # . . discard args - 81 0/subop/add 3/mod/direct 4/rm32/esp . . . . . 8/imm32 # add to esp - # var expected-payload/ebx = ad->curr - 8b/copy 0/mod/indirect 1/rm32/ecx . . . 3/r32/ebx . . # copy *ecx to ebx - # var h/edx: handle = {0, 0} - 68/push 0/imm32 - 68/push 0/imm32 - 89/copy 3/mod/direct 2/rm32/edx . . . 4/r32/esp . . # copy esp to edx - # *Next-alloc-id = 0x34 - c7 0/subop/copy 0/mod/indirect 5/rm32/.disp32 . . . Next-alloc-id/disp32 0x34/imm32 # copy to *Next-alloc-id - # copy-array(ad, src, h) - # . . push args - 52/push-edx - 56/push-esi - 51/push-ecx - # . . call - e8/call copy-array/disp32 - # . . discard args - 81 0/subop/add 3/mod/direct 4/rm32/esp . . . . . 0xc/imm32 # add to esp - # check-ints-equal(h->alloc-id, 0x34, msg) - # . . push args - 68/push "F - test-copy-array: sets alloc-id in handle"/imm32 - 68/push 0x34/imm32 - ff 6/subop/push 0/mod/indirect 2/rm32/edx . . . . . . # push *edx - # . . 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(h->payload, expected-payload, msg) - # . . push args - 68/push "F - test-copy-array: sets payload in handle"/imm32 - 53/push-ebx - ff 6/subop/push 1/mod/*+disp8 2/rm32/edx . . . . 4/disp8 . # push *(edx+4) - # . . 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(h->payload->alloc-id, 0x34, msg) - # . . push args - 68/push "F - test-copy-array: sets alloc-id in payload"/imm32 - 68/push 0x34/imm32 - ff 6/subop/push 0/mod/indirect 2/rm32/edx . . . . . . # push *edx - # . . call - e8/call check-ints-equal/disp32 - # . . discard args - 81 0/subop/add 3/mod/direct 4/rm32/esp . . . . . 0xc/imm32 # add to esp - # var payload/eax: (addr int) = lookup(h) - # . . push args - ff 6/subop/push 1/mod/*+disp8 2/rm32/edx . . . . 4/disp8 . # push *(edx+4) - ff 6/subop/push 0/mod/indirect 2/rm32/edx . . . . . . # push *edx - # . . call - e8/call lookup/disp32 - # . . discard args - 81 0/subop/add 3/mod/direct 4/rm32/esp . . . . . 8/imm32 # add to esp - # check-ints-equal(payload->size, 0xc, msg) - # . . push args - 68/push "F - test-copy-array: sets array size in payload"/imm32 - 68/push 0xc/imm32 - ff 6/subop/push 0/mod/indirect 0/rm32/eax . . . . . . # 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(*Next-alloc-id, 0x35, msg) - # . . push args - 68/push "F - test-copy-array: increments Next-alloc-id"/imm32 - 68/push 0x35/imm32 - ff 6/subop/push 0/mod/indirect 5/rm32/.disp32 . . . Next-alloc-id/disp32 # push *Next-alloc-id - # . . 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 - expected-payload, 12 + 4 for alloc-id + 4 for length, msg) - # . . push args - 68/push "F - test-copy-array: updates allocation descriptor"/imm32 - 68/push 0x14/imm32 - 8b/copy 0/mod/indirect 1/rm32/ecx . . . 0/r32/eax . . # copy *ecx to eax - 29/subtract 3/mod/direct 0/rm32/eax . . . 3/r32/ebx . . # subtract ebx from eax - 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 - # clean up - c7 0/subop/copy 0/mod/indirect 5/rm32/.disp32 . . . Next-alloc-id/disp32 1/imm32 # copy to *Next-alloc-id - # . epilogue - 89/copy 3/mod/direct 4/rm32/esp . . . 5/r32/ebp . . # copy ebp to esp - 5d/pop-to-ebp - c3/return - -# Fill a region of memory with zeroes. -zero-out: # start: (addr byte), len: int - # pseudocode: - # curr/esi = start - # i/ecx = 0 - # while true - # if (i >= len) break - # *curr = 0 - # ++curr - # ++i - # - # . 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 - 52/push-edx - 56/push-esi - # curr/esi = start - 8b/copy 1/mod/*+disp8 5/rm32/ebp . . . 6/r32/esi 8/disp8 . # copy *(ebp+8) to esi - # var i/ecx: int = 0 - 31/xor 3/mod/direct 1/rm32/ecx . . . 1/r32/ecx . . # clear ecx - # edx = len - 8b/copy 1/mod/*+disp8 5/rm32/ebp . . . 2/r32/edx 0xc/disp8 . # copy *(ebp+12) to edx -$zero-out:loop: - # if (i >= len) break - 39/compare 3/mod/direct 1/rm32/ecx . . . 2/r32/edx . . # compare ecx with edx - 7d/jump-if->= $zero-out:end/disp8 - # *curr = 0 - c6 0/subop/copy 0/mod/direct 6/rm32/esi . . . . . 0/imm8 # copy byte to *esi - # ++curr - 46/increment-esi - # ++i - 41/increment-ecx - eb/jump $zero-out:loop/disp8 -$zero-out:end: - # . restore registers - 5e/pop-to-esi - 5a/pop-to-edx - 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-zero-out: - # . prologue - 55/push-ebp - 89/copy 3/mod/direct 5/rm32/ebp . . . 4/r32/esp . . # copy esp to ebp - # region/ecx = 34, 35, 36, 37 - 68/push 0x37363534/imm32 - 89/copy 3/mod/direct 1/rm32/ecx . . . 4/r32/esp . . # copy esp to ecx - # zero-out(ecx, 3) - # . . push args - 68/push 3/imm32/len - 51/push-ecx - # . . call - e8/call zero-out/disp32 - # . . discard args - 81 0/subop/add 3/mod/direct 4/rm32/esp . . . . . 8/imm32 # add to esp - # first 3 bytes cleared, fourth left alone - # . check-ints-equal(*ecx, 0x37000000, msg) - # . . push args - 68/push "F - test-zero-out"/imm32 - 68/push 0x37000000/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 - # . 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 |