# Desugar a few kinds of syntax.
#
# 1.
# $ echo "ab %eax" |./subx run apps/desugar
# ab 3/mod 0/rm32
#
# 2.
# ...
== 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
Entry: # run tests if necessary, convert stdin if not
# initialize heap
# . Heap = new-segment(64KB)
# . . push args
68/push Heap/imm32
68/push 0x10000/imm32/64KB
# . . call
e8/call new-segment/disp32
# . . discard args
81 0/subop/add 3/mod/direct 4/rm32/ESP . . . . . 8/imm32 # add to ESP
# . prolog
89/copy 3/mod/direct 5/rm32/EBP . . . 4/r32/ESP . . # copy ESP to EBP
# - if argc > 1 and argv[1] == "test", then return run_tests()
# . argc > 1
81 7/subop/compare 1/mod/*+disp8 5/rm32/EBP . . . . 0/disp8 1/imm32 # compare *EBP
7e/jump-if-lesser-or-equal $run-main/disp8
# . argv[1] == "test"
# . . push args
68/push "test"/imm32
ff 6/subop/push 1/mod/*+disp8 5/rm32/EBP . . . . 8/disp8 . # push *(EBP+8)
# . . call
e8/call kernel-string-equal?/disp32
# . . discard args
81 0/subop/add 3/mod/direct 4/rm32/ESP . . . . . 8/imm32 # add to ESP
# . check result
3d/compare-EAX-and 1/imm32
75/jump-if-not-equal $run-main/disp8
# . run-tests()
e8/call run-tests/disp32
8b/copy 0/mod/indirect 5/rm32/.disp32 . . 3/r32/EBX Num-test-failures/disp32 # copy *Num-test-failures to EBX
eb/jump $main:end/disp8
$run-main:
# - otherwise convert stdin
# return convert(Stdin, Stdout)
# . . push args
68/push Stdout/imm32
68/push Stdin/imm32
# . . call
e8/call convert/disp32
# . . discard args
81 0/subop/add 3/mod/direct 4/rm32/ESP . . . . . 0x8/imm32 # add to ESP
# . syscall(exit, 0)
bb/copy-to-EBX 0/imm32
$main:end:
b8/copy-to-EAX 1/imm32/exit
cd/syscall 0x80/imm8
convert: # in : (address buffered-file), out : (address buffered-file) -> <void>
# pseudocode:
# var line = new-stream(512, 1)
# while true
# clear-stream(line)
# read-line-buffered(in, line)
# if (line->write == 0) break # end of file
# while true
# var word-slice = next-word(line)
# if slice-empty?(word-slice) # end of line
# break
# if slice-starts-with?(word-slice, "#") # comment
# continue
# if slice-starts-with?(word-slice, '%') # register literal <== what we're here for
# desugar-register(word-slice, out)
# else
# write-slice-buffered(out, word-slice)
# write(out, " ")
# write(out, "\n")
# flush(out)
#
# . prolog
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
# var line/ECX : (address stream byte) = stream(512)
81 5/subop/subtract 3/mod/direct 4/rm32/ESP . . . . . 0x200/imm32 # subtract from ESP
68/push 0x200/imm32/length
68/push 0/imm32/read
68/push 0/imm32/write
89/copy 3/mod/direct 1/rm32/ECX . . . 4/r32/ESP . . # copy ESP to ECX
# var word-slice/EDX = {0, 0}
68/push 0/imm32/end
68/push 0/imm32/start
89/copy 3/mod/direct 2/rm32/EDX . . . 4/r32/ESP . . # copy ESP to EDX
$convert:line-loop:
# clear-stream(line)
# . . push args
51/push-ECX
# . . call
e8/call clear-stream/disp32
# . . discard args
81 0/subop/add 3/mod/direct 4/rm32/ESP . . . . . 4/imm32 # add to ESP
# read-line-buffered(in, line)
# . . push args
51/push-ECX
ff 6/subop/push 1/mod/*+disp8 5/rm32/EBP . . . . 8/disp8 . # push *(EBP+8)
# . . call
e8/call read-line-buffered/disp32
# . . discard args
81 0/subop/add 3/mod/direct 4/rm32/ESP . . . . . 8/imm32 # add to ESP
$convert:check0:
# if (line->write == 0) break
81 7/subop/compare 0/mod/indirect 1/rm32/ECX . . . . . 0/imm32 # compare *ECX
0f 84/jump-if-equal $convert:break/disp32
$convert:word-loop:
# next-word(line, word-slice)
# . . push args
52/push-EDX
51/push-ECX
# . . call
e8/call next-word/disp32
# . . discard args
81 0/subop/add 3/mod/direct 4/rm32/ESP . . . . . 8/imm32 # add to ESP
$convert:check1:
# if (slice-empty?(word-slice)) break
# . EAX = slice-empty?(word-slice)
# . . push args
52/push-EDX
# . . call
e8/call slice-empty?/disp32
# . . discard args
81 0/subop/add 3/mod/direct 4/rm32/ESP . . . . . 4/imm32 # add to ESP
# . if (EAX != 0) break
3d/compare-EAX-and 0/imm32
0f 85/jump-if-not-equal $convert:next-line/disp32
$convert:check-for-comment:
# if (slice-starts-with?(word-slice, "#")) continue
# . start/EBX = word-slice->start
8b/copy 0/mod/indirect 2/rm32/EDX . . . 3/r32/EBX . . # copy *EDX to EBX
# . c/EAX = *start
31/xor 3/mod/direct 0/rm32/EAX . . . 0/r32/EAX . . # clear EAX
8a/copy-byte 0/mod/indirect 3/rm32/EBX . . . 0/r32/AL . . # copy byte at *EBX to AL
# . if (EAX == '#') continue
3d/compare-EAX-and 0x23/imm32/hash
74/jump-if-equal $convert:word-loop/disp8
$convert:check-for-register-literal:
# if (!slice-starts-with?(word-slice, "%")) goto next check
3d/compare-EAX-and 0x25/imm32/percent
75/jump-if-not-equal $convert:regular-word/disp8
$convert:register-literal:
# ++word-slice->start
4b/increment-EBX
# desugar-register(word-slice, out)
# . . push args
52/push-EDX
# . . call
e8/call desugar-register/disp32
# . . discard args
81 0/subop/add 3/mod/direct 4/rm32/ESP . . . . . 4/imm32 # add to ESP
# continue
eb/jump $convert:next-word/disp8
$convert:regular-word:
# write-slice-buffered(out, word-slice)
# . . push args
52/push-EDX
ff 6/subop/push 1/mod/*+disp8 5/rm32/EBP . . . . 0xc/disp8 . # push *(EBP+12)
# . . call
e8/call write-slice-buffered/disp32
# . . discard args
81 0/subop/add 3/mod/direct 4/rm32/ESP . . . . . 8/imm32 # add to ESP
# fall through
$convert:next-word:
# write-buffered(out, " ")
# . . push args
68/push " "/imm32
ff 6/subop/push 1/mod/*+disp8 5/rm32/EBP . . . . 0xc/disp8 . # push *(EBP+12)
# . . call
e8/call write-buffered/disp32
# . . discard args
81 0/subop/add 3/mod/direct 4/rm32/ESP . . . . . 8/imm32 # add to ESP
# loop
eb/jump $convert:word-loop/disp8
$convert:next-line:
# write-buffered(out, "\n")
# . . push args
68/push Newline/imm32
ff 6/subop/push 1/mod/*+disp8 5/rm32/EBP . . . . 0xc/disp8 . # push *(EBP+12)
# . . call
e8/call write-buffered/disp32
# . . discard args
81 0/subop/add 3/mod/direct 4/rm32/ESP . . . . . 8/imm32 # add to ESP
# loop
e9/jump $convert:line-loop/disp32
$convert:break:
# flush(out)
# . . push args
ff 6/subop/push 1/mod/*+disp8 5/rm32/EBP . . . . 0xc/disp8 . # push *(EBP+12)
# . . call
e8/call flush/disp32
# . . discard args
81 0/subop/add 3/mod/direct 4/rm32/ESP . . . . . 4/imm32 # add to ESP
$convert:end:
# . reclaim locals
81 0/subop/add 3/mod/direct 4/rm32/ESP . . . . . 0x214/imm32 # add to ESP
# . restore registers
5b/pop-to-EBX
5a/pop-to-EDX
59/pop-to-ECX
58/pop-to-EAX
# . epilog
89/copy 3/mod/direct 4/rm32/ESP . . . 5/r32/EBP . . # copy EBP to ESP
5d/pop-to-EBP
c3/return
desugar-register: # word : (address slice), out : (address buffered-file)
# . prolog
55/push-EBP
89/copy 3/mod/direct 5/rm32/EBP . . . 4/r32/ESP . . # copy ESP to EBP
# . save registers
50/push-EAX
# reg-num/EAX = get-slice(Registers, word, row-size=8)
# . . push args
68/push "Registers"/imm32
68/push 8/imm32/row-size
ff 6/subop/push 1/mod/*+disp8 5/rm32/EBP . . . . 8/disp8 . # push *(EBP+8)
68/push Registers/imm32
# . . call
e8/call get-slice/disp32
# . . discard args
81 0/subop/add 3/mod/direct 4/rm32/ESP . . . . . 0x10/imm32 # add to ESP
# write-buffered(out, "3/mod/direct ")
# . . push args
68/push "3/mod/direct "/imm32
ff 6/subop/push 1/mod/*+disp8 5/rm32/EBP . . . . 0xc/disp8 . # push *(EBP+12)
# . . call
e8/call write-buffered/disp32
# . . discard args
81 0/subop/add 3/mod/direct 4/rm32/ESP . . . . . 8/imm32 # add to ESP
# print-int32-buffered(out, *EAX)
# . . push args
ff 6/subop/push 0/mod/indirect 0/rm32/EAX . . . . . . # push *EAX
ff 6/subop/push 1/mod/*+disp8 5/rm32/EBP . . . . 0xc/disp8 . # push *(EBP+12)
# . . call
e8/call print-int32-buffered/disp32
# . . discard args
81 0/subop/add 3/mod/direct 4/rm32/ESP . . . . . 8/imm32 # add to ESP
# write-buffered(out, "/rm32")
# . . push args
68/push "/rm32"/imm32
ff 6/subop/push 1/mod/*+disp8 5/rm32/EBP . . . . 0xc/disp8 . # push *(EBP+12)
# . . call
e8/call write-buffered/disp32
# . . discard args
81 0/subop/add 3/mod/direct 4/rm32/ESP . . . . . 8/imm32 # add to ESP
$desugar-register:end:
# . restore registers
58/pop-to-EAX
# . epilog
89/copy 3/mod/direct 4/rm32/ESP . . . 5/r32/EBP . . # copy EBP to ESP
5d/pop-to-EBP
c3/return
test-desugar-register:
# . prolog
55/push-EBP
89/copy 3/mod/direct 5/rm32/EBP . . . 4/r32/ESP . . # copy ESP to EBP
# setup
# . clear-stream(_test-output-stream)
# . . push args
68/push _test-output-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-output-buffered-file+4)
# . . push args
b8/copy-to-EAX _test-output-buffered-file/imm32
05/add-to-EAX 4/imm32
50/push-EAX
# . . call
e8/call clear-stream/disp32
# . . discard args
81 0/subop/add 3/mod/direct 4/rm32/ESP . . . . . 4/imm32 # add to ESP
# var slice/ECX = "eax"
b8/copy-to-EAX "eax"/imm32
8b/copy 0/mod/indirect 0/rm32/EAX . . . 1/r32/ECX . . # copy *EAX to ECX
8d/copy-address 1/mod/*+disp8 4/rm32/sib 0/base/EAX 1/index/ECX . 1/r32/ECX 4/disp8 . # copy EAX+ECX+4 to ECX
05/add-to-EAX 4/imm32
# . ECX = {EAX, ECX}
51/push-ECX
50/push-EAX
89/copy 3/mod/direct 1/rm32/ECX . . . 4/r32/ESP . . # copy ESP to ECX
# desugar-register(str, _test-output-buffered-file)
# . . push args
68/push _test-output-buffered-file/imm32
51/push-ECX
# . . call
e8/call desugar-register/disp32
# . . discard args
81 0/subop/add 3/mod/direct 4/rm32/ESP . . . . . 4/imm32 # add to ESP
# . flush(_test-output-buffered-file)
# . . push args
68/push _test-output-buffered-file/imm32
# . . call
e8/call flush/disp32
# . . discard args
81 0/subop/add 3/mod/direct 4/rm32/ESP . . . . . 4/imm32 # add to ESP
#? # dump output {{{
#? # . write(2/stderr, "^")
#? # . . push args
#? 68/push "^"/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
#? # . write-stream(2/stderr, _test-output-stream)
#? # . . push args
#? 68/push _test-output-stream/imm32
#? 68/push 2/imm32/stderr
#? # . . call
#? e8/call write-stream/disp32
#? # . . discard args
#? 81 0/subop/add 3/mod/direct 4/rm32/ESP . . . . . 8/imm32 # add to ESP
#? # . write(2/stderr, "$\n")
#? # . . push args
#? 68/push "$\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
#? # }}}
# check-stream-equal(_test-output-stream, "3/mod/direct 0/rm32", msg)
# . . push args
68/push "F - test-desugar-register/0"/imm32
68/push "3/mod/direct 0x00000000/rm32"/imm32
68/push _test-output-stream/imm32
# . . call
e8/call check-stream-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-desugar-register-2:
# . prolog
55/push-EBP
89/copy 3/mod/direct 5/rm32/EBP . . . 4/r32/ESP . . # copy ESP to EBP
# setup
# . clear-stream(_test-output-stream)
# . . push args
68/push _test-output-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-output-buffered-file+4)
# . . push args
b8/copy-to-EAX _test-output-buffered-file/imm32
05/add-to-EAX 4/imm32
50/push-EAX
# . . call
e8/call clear-stream/disp32
# . . discard args
81 0/subop/add 3/mod/direct 4/rm32/ESP . . . . . 4/imm32 # add to ESP
# var slice/ECX = "edi"
b8/copy-to-EAX "edi"/imm32
8b/copy 0/mod/indirect 0/rm32/EAX . . . 1/r32/ECX . . # copy *EAX to ECX
8d/copy-address 1/mod/*+disp8 4/rm32/sib 0/base/EAX 1/index/ECX . 1/r32/ECX 4/disp8 . # copy EAX+ECX+4 to ECX
05/add-to-EAX 4/imm32
# . ECX = {EAX, ECX}
51/push-ECX
50/push-EAX
89/copy 3/mod/direct 1/rm32/ECX . . . 4/r32/ESP . . # copy ESP to ECX
# desugar-register(str/ECX, _test-output-buffered-file)
# . . push args
68/push _test-output-buffered-file/imm32
51/push-ECX
# . . call
e8/call desugar-register/disp32
# . . discard args
81 0/subop/add 3/mod/direct 4/rm32/ESP . . . . . 4/imm32 # add to ESP
# . flush(_test-output-buffered-file)
# . . push args
68/push _test-output-buffered-file/imm32
# . . call
e8/call flush/disp32
# . . discard args
81 0/subop/add 3/mod/direct 4/rm32/ESP . . . . . 4/imm32 # add to ESP
#? # dump output {{{
#? # . write(2/stderr, "^")
#? # . . push args
#? 68/push "^"/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
#? # . write-stream(2/stderr, _test-output-stream)
#? # . . push args
#? 68/push _test-output-stream/imm32
#? 68/push 2/imm32/stderr
#? # . . call
#? e8/call write-stream/disp32
#? # . . discard args
#? 81 0/subop/add 3/mod/direct 4/rm32/ESP . . . . . 8/imm32 # add to ESP
#? # . write(2/stderr, "$\n")
#? # . . push args
#? 68/push "$\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
#? # }}}
# check-stream-equal(_test-output-stream, "3/mod/direct 7/rm32", msg)
# . . push args
68/push "F - test-desugar-register/1"/imm32
68/push "3/mod/direct 0x00000007/rm32"/imm32
68/push _test-output-stream/imm32
# . . call
e8/call check-stream-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
== data
Registers: # (table string int)
# a table is a stream
0x40/imm32/write
0/imm32/read
0x40/imm32/length
# data
"eax"/imm32 0/imm32
"ecx"/imm32 1/imm32
"edx"/imm32 2/imm32
"ebx"/imm32 3/imm32
"esp"/imm32 4/imm32
"ebp"/imm32 5/imm32
"esi"/imm32 6/imm32
"edi"/imm32 7/imm32
# . . vim:nowrap:textwidth=0