From 9d27e966b5e9bf1bd3da48f49d7e133d112a2bbe Mon Sep 17 00:00:00 2001 From: Kartik Agaram Date: Fri, 30 Nov 2018 16:45:15 -0800 Subject: 4808 - clean up comments in all subx files --- subx/058read.subx | 48 +++++++++++++++++++++++++----------------------- 1 file changed, 25 insertions(+), 23 deletions(-) (limited to 'subx/058read.subx') diff --git a/subx/058read.subx b/subx/058read.subx index ccd7e349..df301ca8 100644 --- a/subx/058read.subx +++ b/subx/058read.subx @@ -56,7 +56,7 @@ read: # f : fd or (address stream), s : (address stream) -> num-bytes-read/EAX # . prolog 55/push-EBP 89/copy 3/mod/direct 5/rm32/EBP . . . 4/r32/ESP . . # copy ESP to EBP - ## if (f < 0x08000000) return _read(f, s) # f can't be a user-mode address, so treat it as a kernel file descriptor + # if (f < 0x08000000) return _read(f, s) # f can't be a user-mode address, so treat it as a kernel file descriptor 81 7/subop/compare 1/mod/*+disp8 4/rm32/sib 5/base/EBP 4/index/none . . 8/disp8 0x08000000/imm32 # compare *(EBP+8) 7d/jump-if-greater-or-equal $read:fake/disp8 # . . push args @@ -69,7 +69,7 @@ read: # f : fd or (address stream), s : (address stream) -> num-bytes-read/EAX # return eb/jump $read:end/disp8 $read:fake: - ## otherwise, treat 'f' as a stream to scan from + # otherwise, treat 'f' as a stream to scan from # . save registers 56/push-ESI 57/push-EDI @@ -79,19 +79,19 @@ $read:fake: 8b/copy 1/mod/*+disp8 4/rm32/sib 5/base/EBP 4/index/none . 7/r32/EDI 0xc/disp8 . # copy *(EBP+12) to ESI # EAX = _append-4(out = &s->data[s->write], outend = &s->data[s->length], # in = &f->data[f->read], inend = &f->data[f->write]) - # push &f->data[f->write] + # . . push &f->data[f->write] 8b/copy 0/mod/indirect 6/rm32/ESI . . . 0/r32/EAX . . # copy *ESI to EAX 8d/copy-address 1/mod/*+disp8 4/rm32/sib 6/base/ESI 0/index/EAX . 0/r32/EAX 0xc/disp8 . # copy ESI+EAX+12 to EAX 50/push-EAX - # push &f->data[f->read] + # . . push &f->data[f->read] 8b/copy 1/mod/*+disp8 6/rm32/ESI . . . 0/r32/EAX 4/disp8 . # copy *(ESI+4) to EAX 8d/copy-address 1/mod/*+disp8 4/rm32/sib 6/base/ESI 0/index/EAX . 0/r32/EAX 0xc/disp8 . # copy ESI+EAX+12 to EAX 50/push-EAX - # push &s->data[s->length] + # . . push &s->data[s->length] 8b/copy 1/mod/*+disp8 7/rm32/EDI . . . 0/r32/EAX 8/disp8 . # copy *(EDI+8) to EAX 8d/copy-address 1/mod/*+disp8 4/rm32/sib 7/base/EDI 0/index/EAX . 0/r32/EAX 0xc/disp8 . # copy EDI+EAX+12 to EAX 50/push-EAX - # push &s->data[s->write] + # . . push &s->data[s->write] 8b/copy 0/mod/indirect 7/rm32/EDI . . . 0/r32/EAX . . # copy *EDI to EAX 8d/copy-address 1/mod/*+disp8 4/rm32/sib 7/base/EDI 0/index/EAX . 0/r32/EAX 0xc/disp8 . # copy EDI+EAX+12 to EAX 50/push-EAX @@ -112,7 +112,7 @@ $read:end: 5d/pop-to-EBP c3/return -## helpers +# - helpers # idea: a clear-if-empty method on streams that clears only if f.read == f.write # Unclear how I'd use it, though. Callers seem to need the check anyway. @@ -134,13 +134,13 @@ _read: # fd : int, s : (address stream) -> num-bytes-read/EAX # EDX = s->length 8b/copy 1/mod/*+disp8 6/rm32/ESI . . . 2/r32/EDX 8/disp8 . # copy *(ESI+8) to EDX # syscall(read, fd, &s->data[s->write], s->length - s->write) - # fd : EBX + # . . fd : EBX 8b/copy 1/mod/*+disp8 4/rm32/sib 5/base/EBP 4/index/none . 3/r32/EBX 8/disp8 . # copy *(EBP+8) to EBX - # data : ECX = &s->data[s->write] + # . . data : ECX = &s->data[s->write] 8d/copy-address 1/mod/*+disp8 4/rm32/sib 6/base/ESI 0/index/EAX . 1/r32/ECX 0xc/disp8 . # copy ESI+EAX+12 to ECX - # size : EDX = s->length - s->write + # . . size : EDX = s->length - s->write 29/subtract 3/mod/direct 2/rm32/EDX . . . 0/r32/EAX . . # subtract EAX from EDX - # syscall + # . . syscall b8/copy-to-EAX 3/imm32/read cd/syscall 0x80/imm8 # add the result EAX to s->write @@ -176,9 +176,10 @@ _read: # fd : int, s : (address stream) -> num-bytes-read/EAX # use one less register, but doesn't increase the amount of spilling (ECX # and EDX must be used, and EAX must be clobbered anyway). -## tests +# - tests test-read-single: + # - write a single character into _test-stream, then read from its buffered-file # clear-stream(_test-stream) # . . push args 68/push _test-stream/imm32 @@ -222,7 +223,7 @@ test-read-single: # . . push args 68/push "F - test-read-single"/imm32 68/push 0x006241/imm32/Ab - # push *_test-stream-buffer->data + # . . push *_test-stream-buffer->data b8/copy-to-EAX _test-stream-buffer/imm32 ff 6/subop/push 1/mod/*+disp8 0/rm32/EAX . . . . 0xc/disp8 . # push *(EAX+12) # . . call @@ -233,7 +234,7 @@ test-read-single: c3/return test-read-is-stateful: - ## make two consecutive reads, check that their results are appended + # - make two consecutive reads, check that their results are appended # clear-stream(_test-stream) # . . push args 68/push _test-stream/imm32 @@ -284,7 +285,7 @@ test-read-is-stateful: # . . push args 68/push "F - test-read-is-stateful"/imm32 68/push 0x00004443/imm32/C-D - # push *_test-stream-buffer->data + # . push *_test-stream-buffer->data b8/copy-to-EAX _test-stream-buffer/imm32 ff 6/subop/push 1/mod/*+disp8 0/rm32/EAX . . . . 0xc/disp8 . # push *(EAX+12) # . . call @@ -295,22 +296,23 @@ test-read-is-stateful: c3/return test-read-returns-0-on-end-of-file: - ## read after hitting end-of-file, check that result is 0 - # clear-stream(_test-stream) + # - read after hitting end-of-file, check that result is 0 + # setup + # . clear-stream(_test-stream) # . . push args 68/push _test-stream/imm32 # . . call e8/call clear-stream/disp32 # . . discard args 81 0/subop/add 3/mod/direct 4/rm32/ESP . . . . . 4/imm32 # add to ESP - # clear-stream(_test-stream-buffer) + # . clear-stream(_test-stream-buffer) # . . push args 68/push _test-stream-buffer/imm32 # . . call e8/call clear-stream/disp32 # . . discard args 81 0/subop/add 3/mod/direct 4/rm32/ESP . . . . . 4/imm32 # add to ESP - # write(_test-stream, "Ab") + # . write(_test-stream, "Ab") # . . push args 68/push "Ab"/imm32 68/push _test-stream/imm32 @@ -318,8 +320,8 @@ test-read-returns-0-on-end-of-file: e8/call write/disp32 # . . discard args 81 0/subop/add 3/mod/direct 4/rm32/ESP . . . . . 8/imm32 # add to ESP - ## first read gets to end-of-file - # read(_test-stream, _test-stream-buffer) + # first read gets to end-of-file + # . read(_test-stream, _test-stream-buffer) # . . push args 68/push _test-stream-buffer/imm32 68/push _test-stream/imm32 @@ -327,8 +329,8 @@ test-read-returns-0-on-end-of-file: e8/call read/disp32 # . . discard args 81 0/subop/add 3/mod/direct 4/rm32/ESP . . . . . 8/imm32 # add to ESP - ## second read - # read(_test-stream, _test-stream-buffer) + # second read + # . read(_test-stream, _test-stream-buffer) # . . push args 68/push _test-stream-buffer/imm32 68/push _test-stream/imm32 -- cgit 1.4.1-2-gfad0