# new data structure: a slice is an open interval of addresses [start, end) # that includes 'start' but not 'end' == 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 slice-empty?: # s: (addr slice) -> result/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 # ecx = s 8b/copy 1/mod/*+disp8 5/rm32/ebp . . . 1/r32/ecx 8/disp8 . # copy *(ebp+8) to ecx # if (s->start >= s->end) return true # . eax = s->start 8b/copy 0/mod/indirect 1/rm32/ecx . . . 0/r32/eax . . # copy *ecx to eax # . if (eax >= s->end) return true 3b/compare 1/mod/*+disp8 1/rm32/ecx . . . 0/r32/eax 4/disp8 . # compare eax with *(ecx+4) b8/copy-to-eax 1/imm32/true 73/jump-if-addr>= $slice-empty?:end/disp8 b8/copy-to-eax 0/imm32/false $slice-empty?: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 test-slice-empty-true: # . prologue 55/push-ebp 89/copy 3/mod/direct 5/rm32/ebp . . . 4/r32/esp . . # copy esp to ebp # var slice/ecx: slice = {34, 34} 68/push 34/imm32/end 68/push 34/imm32/start 89/copy 3/mod/direct 1/rm32/ecx . . . 4/r32/esp . . # copy esp to ecx # slice-empty?(slice) # . . push args 51/push-ecx # . . call e8/call slice-empty?/disp32 # . . discard args 81 0/subop/add 3/mod/direct 4/rm32/esp . . . . . 4/imm32 # add to esp # check-ints-equal(eax, 1, msg) # . . push args 68/push "F - test-slice-empty-true"/imm32 68/push 1/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 test-slice-empty-false: # . prologue 55/push-ebp 89/copy 3/mod/direct 5/rm32/ebp . . . 4/r32/esp . . # copy esp to ebp # var slice/ecx: slice = {32, 34} 68/push 34/imm32/end 68/push 32/imm32/start 89/copy 3/mod/direct 1/rm32/ecx . . . 4/r32/esp . . # copy esp to ecx # slice-empty?(slice) # . . push args 51/push-ecx # . . call e8/call slice-empty?/disp32 # . . discard args 81 0/subop/add 3/mod/direct 4/rm32/esp . . . . . 4/imm32 # add to esp # check-ints-equal(eax, 0, msg) # . . push args 68/push "F - test-slice-empty-false"/imm32 68/push 0/imm32 50/push-eax # . . call e8/call check-ints-equal/disp32
# Print out a (global variable) string to stdout.
#
# To run:
# $ bootstrap/bootstrap translate ex6.subx -o ex6
# $ bootstrap/bootstrap run ex6
# Hello, world!
== code
# . 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:
# write(stdout, X, Size)
# . fd = 1 (stdout)
bb/copy-to-ebx 1/imm32
# . initialize X (location to write result to)
b9/copy-to-ecx X/imm32
# . initialize Size
8b/copy 0/mod/indirect 5/rm32/.disp32 . . 2/r32/edx Size/disp32 . # copy *Size to edx
# . syscall
e8/call syscall_write/disp32
# exit(ebx)
e8/call syscall_exit/disp32
== data
Size: # size of string
0x0d/imm32 # 13
X: # string to print
48 65 6c 6c 6f 20 77 6f 72 6c 64 21 0a 00
# H e l l o ␣ w o r l d ! newline null
# . . vim:nowrap:textwidth=0