## port of https://github.com/akkartik/crenshaw/blob/master/tutor2.1.pas # corresponds to the section "single digits" in https://compilers.iecc.com/crenshaw/tutor2.txt # # To run: # $ subx translate apps/crenshaw2.1.subx crenshaw 2.1 # $ echo '3' |subx run apps/crenshaw2.1 |xxd - # Expected output: # TODO # # The output is the code a function would need to include, returning the # result in EAX. # # Major note: byte strings are not null-terminated. Instead they're prefixed # with a 32-bit length. == code # instruction effective address operand 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 # main: # abort(Error_integer) # push args 68/push . . . . . . . Error_integer/imm32 # call e8/call . . . . . . abort/disp32 # discard arg 81 0/subop/add 3/mod/direct 4/rm32/ESP . . . . . 4/imm32 # add 4 to ESP # exit(0) bb/copy . . . . . . . 0/imm32 # copy 0 to EBX b8/copy . . . . . . . 1/imm32/exit # copy 1 to EAX cd/syscall . . . . . . . 0x80/imm8 # int 80h # print error message and exit # really maps to the 'Expected' function in Crenshaw abort: # s : (address array byte) -> # error(s) # push args ff 6/subop/push 1/mod/*+disp8 4/rm32/sib 4/base/ESP 4/index/none . . 4/disp8 . # push *(ESP+4) # call e8/call . . . . . . error/disp32 # discard arg 81 0/subop/add 3/mod/direct 4/rm32/ESP . . . . . 4/imm32 # add 4 to ESP # exit(1) bb/copy . . . . . . . 1/imm32 # copy 1 to EBX b8/copy . . . . . . . 1/imm32/exit # copy 1 to EAX cd/syscall . . . . . . . 0x80/imm8 # int 80h # print out "Error: #{s} expected\n" to stderr error: # s : (address array byte) -> # write_stderr("Error: ") # push args 68/push . . . . . . . Error/imm32 # call e8/call . . . . . . write_stderr/disp32 # discard arg 81 0/subop/add 3/mod/direct 4/rm32/ESP . . . . . 4/imm32 # add 4 to ESP # write_stderr(s) # push args ff 6/subop/push 1/mod/*+disp8 4/rm32/sib 4/base/ESP 4/index/none . . 4/disp8 . # push *(ESP+4) # call e8/call . . . . . . write_stderr/disp32 # discard arg 81 0/subop/add 3/mod/direct 4/rm32/ESP . . . . . 4/imm32 # add 4 to ESP # write_stderr(" expected") # push args 68/push . . . . . . . Expected_suffix/imm32 # call e8/call . . . . . . write_stderr/disp32 # discard arg 81 0/subop/add 3/mod/direct 4/rm32/ESP . . . . . 4/imm32 # add 4 to ESP # write_stderr("\n") # push args 68/push . . . . . . . Newline/imm32 # call e8/call . . . . . . write_stderr/disp32 # discard arg 81 0/subop/add 3/mod/direct 4/rm32/ESP . . . . . 4/imm32 # add 4 to ESP # end c3/return write_stderr: # s : (address array byte) -> # write(2/stderr, (data) s+4, (size) *s) # fd = 2 (stderr) bb/copy . . . . . . . 2/imm32 # copy 2 to EBX # x = s+4 8b/copy 1/mod/*+disp8 4/rm32/SIB 4/base/ESP 4/index/none . 1/r32/ECX 4/disp8 . # copy *(ESP+4) to ECX 81 0/subop/add 3/mod/direct 1/rm32/ECX . . . . . 4/imm32 # add 4 to ECX # size = *s 8b/copy 1/mod/*+disp8 4/rm32/SIB 4/base/ESP 4/index/none . 2/r32/EDX 4/disp8 . # copy *(ESP+4) to EDX 8b/copy 0/mod/indirect 2/rm32/EDX . . . 2/r32/EDX . . # copy *EDX to EDX # call write() b8/copy . . . . . . . 4/imm32/write # copy 1 to EAX cd/syscall . . . . . . . 0x80/imm8 # int 80h # end c3/return write_stdout: # s : (address array byte) -> # write(1/stdout, (data) s+4, (size) *s) # fd = 1 (stdout) bb/copy . . . . . . . 1/imm32 # copy 1 to EBX # x = s+4 8b/copy 1/mod/*+disp8 4/rm32/SIB 4/base/ESP 4/index/none . 1/r32/ECX 4/disp8 . # copy *(ESP+4) to ECX 81 0/subop/add 3/mod/direct 1/rm32/ECX . . . . . 4/imm32 # add 4 to ECX # size = *s 8b/copy 1/mod/*+disp8 4/rm32/SIB 4/base/ESP 4/index/none . 2/r32/EDX 4/disp8 . # copy *(ESP+4) to EDX 8b/copy 0/mod/indirect 2/rm32/EDX . . . 2/r32/EDX . . # copy *EDX to EDX # call write() b8/copy . . . . . . . 4/imm32/write # copy 1 to EAX cd/syscall . . . . . . . 0x80/imm8 # int 80h # end c3/return == data Newline: # size 01 00 00 00 # data 0a/newline Error: # "Error: " : (array byte) # size 07 00 00 00 # data 45/E 72/r 72/r 6f/o 72/r 3a/: 20/space Expected_suffix: # " expected" : (array byte) # size 09 00 00 00 # data 20/space 65/e 78/x 70/p 65/e 63/c 74/t 65/e 64/d Error_integer: # "Integer" : (array byte) # size 07 00 00 00 # data 49/I 6e/n 74/t 65/e 67/g 65/e 72/r