119 lines
6.2 KiB
Plaintext
119 lines
6.2 KiB
Plaintext
# Helper to allocate a stream on the heap.
|
|
|
|
== 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
|
|
|
|
new-stream: # ad : (address allocation-descriptor), length : int, elemsize : int -> address/EAX
|
|
# . prolog
|
|
55/push-EBP
|
|
89/copy 3/mod/direct 5/rm32/EBP . . . 4/r32/ESP . . # copy ESP to EBP
|
|
# . save registers
|
|
52/push-EDX
|
|
# n = elemsize * length + 12 (for read, write and length)
|
|
# . EAX = elemsize
|
|
8b/copy 1/mod/*+disp8 5/rm32/EBP . . . 0/r32/EAX 0x10/disp8 . # copy *(EBP+16) to EAX
|
|
# . EAX *= length
|
|
31/xor 3/mod/direct 2/rm32/EDX . . . 2/r32/EDX . . # clear EDX
|
|
f7 4/subop/multiply 1/mod/*+disp8 5/rm32/EBP . . 0xc/disp8 . # multiply *(EBP+12) into EAX
|
|
# . if overflow abort
|
|
81 7/subop/compare 3/mod/direct 2/rm32/EDX . . . . . 0/imm32 # compare EDX
|
|
75/jump-if-not-equal $new-stream:abort/disp8
|
|
# . EDX = elemsize*length
|
|
89/copy 3/mod/direct 2/rm32/EDX . . . 0/r32/EAX . . # copy EAX to EDX
|
|
# . EAX += 12
|
|
05/add-to-EAX 0xc/imm32
|
|
# allocate(ad, n)
|
|
# . . push args
|
|
50/push-EAX
|
|
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
|
|
# EAX->length = elemsize*length
|
|
89/copy 1/mod/*+disp8 0/rm32/EAX . . . 2/r32/EDX 8/disp8 . # copy EDX to *(EAX+8)
|
|
# clear-stream(EAX)
|
|
# . . push args
|
|
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
|
|
$new-stream:end:
|
|
# . restore registers
|
|
5a/pop-to-EDX
|
|
# . epilog
|
|
89/copy 3/mod/direct 4/rm32/ESP . . . 5/r32/EBP . . # copy EBP to ESP
|
|
5d/pop-to-EBP
|
|
c3/return
|
|
|
|
$new-stream:abort:
|
|
# . _write(2/stderr, error)
|
|
# . . push args
|
|
68/push "new-stream: size too large\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
|
|
b8/copy-to-EAX 1/imm32/exit
|
|
cd/syscall 0x80/imm8
|
|
# never gets here
|
|
|
|
test-new-stream:
|
|
# . prolog
|
|
55/push-EBP
|
|
89/copy 3/mod/direct 5/rm32/EBP . . . 4/r32/ESP . . # copy ESP to EBP
|
|
# var heap/ECX : (address allocation-descriptor) = {0, 0}
|
|
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
|
|
# heap = 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 start/EDX = ad->curr
|
|
8b/copy 0/mod/indirect 1/rm32/ECX . . . 2/r32/EDX . . # copy *ECX to EDX
|
|
# EAX = new-stream(heap, 3, 2)
|
|
# . . push args
|
|
68/push 2/imm32
|
|
68/push 3/imm32
|
|
51/push-ECX
|
|
# . . call
|
|
e8/call new-stream/disp32
|
|
# . . discard args
|
|
81 0/subop/add 3/mod/direct 4/rm32/ESP . . . . . 0xc/imm32 # add to ESP
|
|
# check-ints-equal(EAX, EDX, msg)
|
|
# . . push args
|
|
68/push "F - test-new-stream: returns current pointer of allocation descriptor"/imm32
|
|
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
|
|
# check-ints-equal(EAX->length, 6, msg)
|
|
# . . push args
|
|
68/push "F - test-new-stream: sets length correctly"/imm32
|
|
68/push 6/imm32
|
|
ff 6/subop/push 1/mod/*+disp8 0/rm32/EAX . . . . . 8/disp8 # push *(EAX+8)
|
|
# . . call
|
|
e8/call check-ints-equal/disp32
|
|
# . . discard args
|
|
81 0/subop/add 3/mod/direct 4/rm32/ESP . . . . . 0xc/imm32 # add to ESP
|
|
# the rest is delegated to clear-stream() so we won't bother checking it
|
|
# . epilog
|
|
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
|