generating code for casts!

This commit is contained in:
pommicket 2022-02-10 21:09:52 -05:00
parent bba56d2b51
commit 017a70ee7e
8 changed files with 423 additions and 101 deletions

View file

@ -21,6 +21,7 @@ global codegen_second_pass ; = 0 on first global pass, 1 on second global pass
global functions_addresses ; ident list of addresses
global functions_labels ; ident list of ident lists of label addresses
global curr_function_labels ; ident list of labels for current function (written to in 1st pass, read from in 2nd pass)
global curr_function_return_type
#define REG_RAX 0
#define REG_RBX 3
@ -76,7 +77,72 @@ function emit_mov_reg
*1code_output = n
code_output += 1
return
function emit_mov_rax_imm64
argument imm64
; 48 b8 IMM64
*2code_output = 0xb848
code_output += 2
*8code_output = imm64
code_output += 8
return
function emit_movsx_rax_al
; 48 0f be c0
*4code_output = 0xc0be0f48
code_output += 4
return
function emit_movsx_rax_ax
; 48 0f bf c0
*4code_output = 0xc0bf0f48
code_output += 4
return
function emit_movsx_rax_eax
; 48 63 c0
*2code_output = 0x6348
code_output += 2
*1code_output = 0xc0
code_output += 1
return
function emit_movzx_rax_al
; 48 0f b6 c0
*4code_output = 0xc0b60f48
code_output += 4
return
function emit_movzx_rax_ax
; 48 0f b7 c0
*4code_output = 0xc0b70f48
code_output += 4
return
function emit_mov_eax_eax
; 89 c0
*2code_output = 0xc089
code_output += 2
return
function emit_mov_qword_rsp_plus_imm32_rax
argument imm32
; 48 89 84 24 IMM32
*4code_output = 0x24848948
code_output += 4
*4code_output = imm32
code_output += 4
return
function emit_mov_rax_qword_rsp_plus_imm32
argument imm32
; 48 8b 84 24 IMM32
*4code_output = 0x24848b48
code_output += 4
*4code_output = imm32
code_output += 4
return
function emit_sub_rsp_imm32
argument imm32
@ -117,33 +183,6 @@ function emit_ret
code_output += 1
return
function emit_mov_qword_rsp_plus_imm32_rax
argument imm32
; 48 89 84 24 IMM32
*4code_output = 0x24848948
code_output += 4
*4code_output = imm32
code_output += 4
return
function emit_mov_rax_qword_rsp_plus_imm32
argument imm32
; 48 8b 84 24 IMM32
*4code_output = 0x24848b48
code_output += 4
*4code_output = imm32
code_output += 4
return
function emit_mov_rax_imm64
argument imm64
; 48 b8 IMM64
*2code_output = 0xb848
code_output += 2
*8code_output = imm64
code_output += 8
return
function emit_call_rax
; ff d0
*2code_output = 0xd0ff
@ -185,6 +224,59 @@ function emit_movsq
code_output += 2
return
function emit_movss_xmm0_dword_rax
; f3 0f 10 00
*4code_output = 0x00100ff3
code_output += 4
return
function emit_movsd_xmm0_qword_rax
; f2 0f 10 00
*4code_output = 0x00100ff2
code_output += 4
return
function emit_movss_dword_rax_xmm0
; f3 0f 11 00
*4code_output = 0x00110ff3
code_output += 4
return
function emit_movsd_qword_rax_xmm0
; f2 0f 11 00
*4code_output = 0x00110ff2
code_output += 4
return
function emit_cvtss2sd_xmm0_xmm0
; f3 0f 5a c0
*4code_output = 0xc05a0ff3
code_output += 4
return
function emit_cvtsd2ss_xmm0_xmm0
; f2 0f 5a c0
*4code_output = 0xc05a0ff2
code_output += 4
return
function emit_cvttsd2si_rax_xmm0
; f2 48 0f 2c c0
*4code_output = 0x2c0f48f2
code_output += 4
*1code_output = 0xc0
code_output += 1
return
function emit_cvtsi2sd_xmm0_rax
; f2 48 0f 2a c0
*4code_output = 0x2a0f48f2
code_output += 4
*1code_output = 0xc0
code_output += 1
return
; make sure you put the return value in the proper place before calling this
function generate_return
emit_mov_reg(REG_RSP, REG_RBP)
@ -193,24 +285,6 @@ function generate_return
emit_ret()
return
; returns pointer to end of expression
function generate_push_expression
argument expr
local c
c = *1expr
if c == EXPRESSION_CONSTANT_INT goto generate_push_int
die(.str_genpushexprNI)
:str_genpushexprNI
string generate_push_expression not implemented.
byte 0
:generate_push_int
expr += 8
emit_mov_rax_imm64(*8expr)
emit_push_rax()
expr += 8
return expr
; copy sizeof(type) bytes, rounded up to the nearest 8, from rsi to rdi
function generate_copy_rsi_to_rdi_qwords
argument type
@ -230,6 +304,225 @@ function generate_copy_rsi_to_rdi_qwords
emit_movsq()
return
; cast whatever was just pushed onto the stack from from_type to to_type
; `statement` is used for errors
function generate_cast_top_of_stack
argument statement
argument from_type
argument to_type
local from
local to
local c
local d
from = types + from_type
to = types + to_type
if *1to == TYPE_VOID goto return_0 ; cast to void my ass
if *1from == TYPE_VOID goto bad_gen_cast ; cast from void to something - that's bad
if *1from == TYPE_ARRAY goto bad_gen_cast ; cast array (this probably won't ever happen because of decaying)
if *1to == TYPE_ARRAY goto bad_gen_cast ; cast to array
if *1from == TYPE_FUNCTION goto bad_gen_cast ; shouldn't happen
if *1to == TYPE_FUNCTION goto bad_gen_cast ; shouldn't happen
if *1to == TYPE_STRUCT goto gen_cast_to_struct
if *1from == TYPE_STRUCT goto bad_gen_cast ; cast from struct to something else
if *1to < TYPE_FLOAT goto gen_cast_to_integer
if *1to == TYPE_POINTER goto gen_cast_to_integer ; pointers are basically integers
; cast to float/double
if *1from == TYPE_POINTER goto bad_gen_cast ; pointer to float/double
if *1to == *1from goto return_0
if *1from == TYPE_DOUBLE goto gen_cast_double_to_float
if *1from == TYPE_FLOAT goto gen_cast_float_to_double
; int to float/double
if *1to == TYPE_FLOAT goto gen_cast_int_to_float
if *1to == TYPE_DOUBLE goto gen_cast_int_to_double
goto bad_gen_cast ; in theory we shouldn't get here
:gen_cast_to_integer
if *1from == *1to goto return_0 ; casting from type to same type
if *1from == TYPE_POINTER goto return_0 ; no need to do anything
; cast float/double to integer
if *1from == TYPE_FLOAT goto gen_cast_float_to_int
if *1from == TYPE_DOUBLE goto gen_cast_double_to_int
c = type_sizeof(*1from)
d = type_sizeof(*1to)
if d > c goto return_0 ; casting to bigger type, so we're good
if c == 8 goto return_0 ; casting from unsigned/signed long to unsigned/signed long, we're good
; mov rax, [rsp]
emit_mov_rax_qword_rsp_plus_imm32(0)
; now sign/zero extend the lower part of rax to the whole of rax
if *1to == TYPE_CHAR goto gen_cast_integer_to_signed_char
if *1to == TYPE_UNSIGNED_CHAR goto gen_cast_integer_to_unsigned_char
if *1to == TYPE_SHORT goto gen_cast_integer_to_signed_short
if *1to == TYPE_UNSIGNED_SHORT goto gen_cast_integer_to_unsigned_short
if *1to == TYPE_INT goto gen_cast_integer_to_signed_int
if *1to == TYPE_UNSIGNED_INT goto gen_cast_integer_to_unsigned_int
goto bad_gen_cast ; in theory we shouldn't get here
:int2int_cast_cont
; mov [rsp], rax
emit_mov_qword_rsp_plus_imm32_rax(0)
return
:gen_cast_integer_to_signed_char
emit_movsx_rax_al()
goto int2int_cast_cont
:gen_cast_integer_to_unsigned_char
emit_movzx_rax_al()
goto int2int_cast_cont
:gen_cast_integer_to_signed_short
emit_movsx_rax_ax()
goto int2int_cast_cont
:gen_cast_integer_to_unsigned_short
emit_movzx_rax_ax()
goto int2int_cast_cont
:gen_cast_integer_to_signed_int
emit_movsx_rax_eax()
goto int2int_cast_cont
:gen_cast_integer_to_unsigned_int
emit_mov_eax_eax()
goto int2int_cast_cont
:gen_cast_to_struct
; this is necessary because we add an implicit cast for return values
; so if we didn't have this, we wouldn't be able to return structs.
if *1from != TYPE_STRUCT goto bad_gen_cast
from += 1
to += 1
if *8from != *8to goto bad_gen_cast
return ; no casting needed; these are the same type
:gen_cast_double_to_float
; mov rax, rsp
emit_mov_reg(REG_RAX, REG_RSP)
; movsd xmm0, [rax]
emit_movsd_xmm0_qword_rax()
; cvtsd2ss xmm0, xmm0
emit_cvtsd2ss_xmm0_xmm0()
; movsd [rax], xmm0
emit_movsd_qword_rax_xmm0()
return
:gen_cast_float_to_double
; mov rax, rsp
emit_mov_reg(REG_RAX, REG_RSP)
; movss xmm0, [rax]
emit_movss_xmm0_dword_rax()
; cvtss2sd xmm0, xmm0
emit_cvtss2sd_xmm0_xmm0()
; movss [rax], xmm0
emit_movss_dword_rax_xmm0()
return
:gen_cast_int_to_float
; to reduce # of instructions, we first convert int to double, then double to float
; mov rax, [rsp]
emit_mov_rax_qword_rsp_plus_imm32(0)
; cvtsi2sd xmm0, rax
emit_cvtsi2sd_xmm0_rax()
; cvtsd2ss xmm0, xmm0
emit_cvtsd2ss_xmm0_xmm0()
; mov rax, rsp
emit_mov_reg(REG_RAX, REG_RSP)
; movss [rax], xmm0
emit_movss_dword_rax_xmm0()
; it shouldn't matter that there's junk at [rsp+4]
return
:gen_cast_int_to_double
; mov rax, [rsp]
emit_mov_rax_qword_rsp_plus_imm32(0)
; cvtsi2sd xmm0, rax
emit_cvtsi2sd_xmm0_rax()
; mov rax, rsp
emit_mov_reg(REG_RAX, REG_RSP)
; movsd [rax], xmm0
emit_movsd_qword_rax_xmm0()
return
:gen_cast_float_to_int
; mov rax, rsp
emit_mov_reg(REG_RAX, REG_RSP)
; movss xmm0, [rax]
emit_movss_xmm0_dword_rax()
; convert float to double, then double to int
; cvtss2sd xmm0, xmm0
emit_cvtss2sd_xmm0_xmm0()
; cvttsd2si rax, xmm0
emit_cvttsd2si_rax_xmm0()
; mov [rsp], rax
emit_mov_qword_rsp_plus_imm32_rax(0)
return
:gen_cast_double_to_int
; mov rax, rsp
emit_mov_reg(REG_RAX, REG_RSP)
; movsd xmm0, [rax]
emit_movsd_xmm0_qword_rax()
; cvttsd2si rax, xmm0
emit_cvttsd2si_rax_xmm0()
; mov [rsp], rax
emit_mov_qword_rsp_plus_imm32_rax(0)
return
:bad_gen_cast
print_statement_location(statement)
puts(.str_bad_gen_cast1)
print_type(from_type)
puts(.str_bad_gen_cast2)
print_type(to_type)
putc(10)
exit(1)
:str_bad_gen_cast1
string : Error: Cannot convert type
byte 32
byte 0
:str_bad_gen_cast2
string to type
byte 32
byte 0
; `statement` is used for errors
; returns pointer to end of expression
function generate_push_expression
argument statement
argument expr
local b
local c
local type
type = expr + 4
type = *4type
c = *1expr
if c == EXPRESSION_CONSTANT_INT goto generate_push_int
if c == EXPRESSION_CONSTANT_FLOAT goto generate_push_float
if c == EXPRESSION_CAST goto generate_cast
die(.str_genpushexprNI)
:str_genpushexprNI
string generate_push_expression not implemented.
byte 0
:generate_cast
expr += 4
c = *4expr ; cast type
expr += 8
b = *4expr ; original type
expr -= 4
expr = generate_push_expression(statement, expr)
generate_cast_top_of_stack(statement, b, c)
return expr
:generate_push_float
expr += 8
emit_mov_rax_imm64(*8expr)
emit_push_rax()
generate_cast_top_of_stack(statement, TYPE_DOUBLE, type)
expr += 8
return expr
:generate_push_int
expr += 8
emit_mov_rax_imm64(*8expr)
emit_push_rax()
expr += 8
return expr
function generate_statement
argument statement
local dat1
@ -268,22 +561,29 @@ function generate_statement
return
:gen_return
if dat1 == 0 goto gen_return_noexpr
generate_push_expression(dat1)
generate_push_expression(statement, dat1)
p = dat1 + 4 ; pointer to dat1 type
generate_cast_top_of_stack(statement, *4p, curr_function_return_type)
; copy sizeof(return expression) rounded up to 8 bytes from [rsp] to [rbp+16]
emit_mov_reg(REG_RSI, REG_RSP)
emit_lea_rax_rbp_plus_imm32(16)
emit_mov_reg(REG_RDI, REG_RAX)
p = dat1 + 4
generate_copy_rsi_to_rdi_qwords(*4p)
:gen_return_noexpr
generate_return()
return
function generate_function
argument function_name
argument function_statement
local function_type
local out0
function_type = ident_list_lookup(function_types, function_name)
curr_function_return_type = functype_return_type(function_type)
if codegen_second_pass != 0 goto genf_second_pass
curr_function_labels = ident_list_create(4000) ; ~ 200 labels per function should be plenty
ident_list_add(functions_labels, function_name, curr_function_labels)
@ -334,8 +634,8 @@ function generate_functions
:function_addr_mismatch
; address of function on 2nd pass doesn't line up with 1st pass
fputs(2, .str_function_addr_mismatch)
fputs(2, function_name)
puts(.str_function_addr_mismatch)
puts(function_name)
exit(1)
:str_function_addr_mismatch
string Function address on first pass doesn't match 2nd pass:

View file

@ -108,27 +108,31 @@ function types_init
p += 1
*8ptypes_bytes_used = p - types
return
function fprint_token_location
argument fd
argument token
token += 2
fprint_filename(fd, *2token)
token += 2
fputc(fd, ':)
fputn(fd, *4token)
return
function print_token_location
argument token
token += 2
print_filename(*2token)
token += 2
putc(':)
putn(*4token)
return
function print_statement_location
argument statement
; statements & tokens have the same format for locations!
print_token_location(statement)
return
; accepts EITHER file index OR pointer to filename
function fprint_filename
argument fd
function print_filename
argument file
if file ] 65535 goto print_filename_string
file = file_get(file)
; (fallthrough)
:print_filename_string
fputs(2, file)
puts(file)
return
; accepts EITHER file index OR pointer to filename
@ -136,12 +140,12 @@ function compile_error
argument file
argument line
argument message
fprint_filename(2, file)
fputc(2, ':)
fputn(2, line)
fputs(2, .str_error_prefix)
fputs(2, message)
fputc(2, 10)
print_filename(file)
putc(':)
putn(line)
puts(.str_error_prefix)
puts(message)
putc(10)
exit(1)
function token_error
@ -161,12 +165,12 @@ function compile_warning
argument file
argument line
argument message
fprint_filename(2, file)
fputc(2, ':)
fputn(2, line)
fputs(2, .str_warning_prefix)
fputs(2, message)
fputc(2, 10)
print_filename(file)
putc(':)
putn(line)
puts(.str_warning_prefix)
puts(message)
putc(10)
return
:str_error_prefix
@ -306,7 +310,7 @@ function main
byte 0
:mmap_output_fd_failed
fputs(2, .str_mmap_output_fd_failed)
puts(.str_mmap_output_fd_failed)
exit(1)
:str_mmap_output_fd_failed
string Couldn't mmap output file.
@ -314,7 +318,7 @@ function main
byte 0
:usage_error
fputs(2, .str_usage_error)
puts(.str_usage_error)
exit(1)
:str_usage_error

View file

@ -14,5 +14,5 @@ struct B { struct A *blah; }
*/
int main(int argc, char **argv) {
return 42;
return (float)(long)"hello";
}

View file

@ -843,7 +843,9 @@ function parse_statement
if *1token == SYMBOL_SEMICOLON goto return_no_expr
n = token_next_semicolon_not_in_brackets(token)
*8out = expressions_end
p = expressions_end + 4 ; type of expression
expressions_end = parse_expression(token, n, expressions_end)
type_decay_array_to_pointer_in_place(*4p)
token = n + 16
:return_no_expr
out += 32
@ -2400,7 +2402,7 @@ function type_length
type += type_length(type)
return type - start
:type_length_not_function
fputs(2, .str_type_length_bad_type)
puts(.str_type_length_bad_type)
exit(1)
:str_type_length_bad_type
string Bad type passed to type_length. This shouldn't happen.
@ -2606,7 +2608,7 @@ function parse_expression
if c == EXPRESSION_DIV goto type_binary_usual
if c == EXPRESSION_REMAINDER goto type_binary_usual_integer
fputs(2, .str_binop_this_shouldnt_happen)
puts(.str_binop_this_shouldnt_happen)
exit(1)
:str_binop_this_shouldnt_happen
string Bad binop symbol (this shouldn't happen).
@ -2769,7 +2771,7 @@ function parse_expression
if c == EXPRESSION_DEREFERENCE goto unary_dereference
if c == EXPRESSION_PRE_INCREMENT goto unary_type_scalar_nopromote
if c == EXPRESSION_PRE_DECREMENT goto unary_type_scalar_nopromote
fputs(2, .str_unop_this_shouldnt_happen)
puts(.str_unop_this_shouldnt_happen)
exit(1)
:str_unop_this_shouldnt_happen
string Bad unary symbol (this shouldn't happen).
@ -2798,7 +2800,9 @@ function parse_expression
*4out = a
out += 4
p += 16
a = out + 4 ; pointer to casted expression type
out = parse_expression(p, tokens_end, out)
type_decay_array_to_pointer_in_place(*4a)
return out
:bad_cast
token_error(tokens, .str_bad_cast)
@ -2840,7 +2844,7 @@ function parse_expression
*4type = a
return out
:unary_bad_type
fprint_token_location(1, tokens)
print_token_location(tokens)
puts(.str_unary_bad_type)
print_type(a)
putc(10)
@ -3244,7 +3248,7 @@ function type_sizeof
if c == TYPE_ARRAY goto sizeof_array
if c == TYPE_STRUCT goto sizeof_struct
fputs(2, .str_sizeof_bad)
puts(.str_sizeof_bad)
exit(1)
:str_sizeof_bad
string type_sizeof bad type.
@ -3309,7 +3313,7 @@ function type_alignof
if c == TYPE_ARRAY goto alignof_array
if c == TYPE_STRUCT goto alignof_struct
fputs(2, .str_alignof_bad)
puts(.str_alignof_bad)
exit(1)
:str_alignof_bad
string type_alignof bad type.
@ -3637,7 +3641,7 @@ function fit_to_type
if c == TYPE_LONG goto fit_to_type_long
if c == TYPE_UNSIGNED_LONG goto fit_to_type_ulong
if c == TYPE_POINTER goto fit_to_type_ulong
fputs(2, .str_bad_fit_to_type)
puts(.str_bad_fit_to_type)
exit(1)
:str_bad_fit_to_type
string Bad type passed to fit_to_type.
@ -3726,7 +3730,7 @@ function bad_types_to_operator
argument type1
argument type2
fprint_token_location(1, token)
print_token_location(token)
puts(.str_bad_types_to_operator)
print_type(type1)
puts(.str_space_and_space)
@ -4276,7 +4280,7 @@ function print_type
if c == TYPE_ARRAY goto print_type_array
if c == TYPE_STRUCT goto print_type_struct
if c == TYPE_FUNCTION goto print_type_function
fputs(2, .str_bad_print_type)
puts(.str_bad_print_type)
putnln(type)
putnln(c)
putnln(types_bytes_used)

View file

@ -603,10 +603,10 @@ function translation_phase_4
if b != 0 goto pp_directive_endif
goto unrecognized_directive
:pp_directive_error
fputs(2, filename)
fputc(2, ':)
fputn(2, line_number)
fputs(2, .str_directive_error)
puts(filename)
putc(':)
putn(line_number)
puts(.str_directive_error)
exit(1)
:str_directive_error
string : #error

View file

@ -15,7 +15,7 @@ function file_get
:file_got
return p
:file_uhoh
fputs(2, .str_bad_file_index)
puts(.str_bad_file_index)
exit(1)
:str_bad_file_index
string Bad file index. This shouldn't happen.
@ -609,7 +609,7 @@ function print_tokens
if *1p == TOKEN_STRING_LITERAL goto print_token_string_literal
if *1p == TOKEN_IDENTIFIER goto print_token_identifier
if *1p == TOKEN_EOF goto print_token_eof
fputs(2, .str_print_bad_token)
puts(.str_print_bad_token)
exit(1)
:print_token_keyword
s = get_keyword_str(*1p)

View file

@ -137,9 +137,9 @@ function max_signed
function file_error
argument name
fputs(2, .str_file_error)
fputs(2, name)
fputc(2, 10)
puts(.str_file_error)
puts(name)
putc(10)
exit(1)
:str_file_error
@ -149,8 +149,8 @@ function file_error
function die
argument message
fputs(2, message)
fputc(2, 10)
puts(message)
putc(10)
exit(1)
function ftruncate
@ -162,7 +162,7 @@ function ftruncate
return
:ftruncate_failed
fputs(2, .str_ftruncate_failed)
puts(.str_ftruncate_failed)
exit(1)
:str_ftruncate_failed
string ftruncated failed.
@ -200,7 +200,7 @@ function malloc
return memory + 8
:malloc_failed
fputs(2, .str_out_of_memory)
puts(.str_out_of_memory)
exit(1)
:str_out_of_memory
@ -768,7 +768,7 @@ function leftmost_1bit
:leftmost1bit_found
return i
:leftmost1bit_0
fputs(2, .str_leftmost1bit_0)
puts(.str_leftmost1bit_0)
exit(1)
:str_leftmost1bit_0
string 0 passed to leftmost_1bit.

View file

@ -119,6 +119,12 @@ ax bx cx dx sp bp si di
│ mov r8, rax │ 49 89 c0 │ set r8 to rax (only used for syscalls) │
│ mov r9, rax │ 49 89 c1 │ set r9 to rax (only used for syscalls) │
│ mov r10, rax │ 49 89 c2 │ set r10 to rax (only used for syscalls)│
| movsx rax, al | 48 0f be c0 | sign-extend al to rax |
| movsx rax, ax | 48 0f bf c0 | sign-extend ax to rax |
| movsx rax, eax | 48 63 c0 | sign-extend eax to rax |
| movzx rax, al | 48 0f b6 c0 | zero-extend al to rax |
| movzx rax, ax | 48 0f b7 c0 | zero-extend ax to rax |
| mov eax, eax | 89 c0 | zero-extend eax to rax |
│ xchg rax, rbx │ 48 93 │ exchange the values of rax and rbx │
│ mov [rbx], rax │ 48 89 03 │ store rax as 8 bytes at address rbx │
│ mov rax, [rbx] │ 48 8b 03 │ load 8 bytes from address rbx into rax │
@ -175,6 +181,14 @@ ax bx cx dx sp bp si di
│ ja IMM32 │ 0f 87 IMM32 │ jump if "above" (like jg but unsigned) │
│ jbe IMM32 │ 0f 86 IMM32 │ jump if below or equal to │
│ jae IMM32 │ 0f 83 IMM32 │ jump if above or equal to │
│ movss xmm0, [rax] │ f3 0f 10 00 │ load the float at *rax into xmm0 │
│ movsd xmm0, [rax] │ f2 0f 10 00 │ load the double at *rax into xmm0 │
│ movss [rax], xmm0 │ f3 0f 11 00 │ store the float in xmm0 at *rax │
│ movsd [rax], xmm0 │ f2 0f 11 00 │ store the double in xmm0 at *rax │
| cvtss2sd xmm0, xmm0 | f3 0f 5a c0 | convert xmm0 from float to double |
| cvtsd2ss xmm0, xmm0 | f2 0f 5a c0 | convert xmm0 from double to float |
| cvttsd2si rax, xmm0 | f2 48 0f 2c c0 | convert double in xmm0 to int in rax |
| cvtsi2sd xmm0, rax | f2 48 0f 2a c0 | convert int in rax to double in xmm0 |
│ call rax │ ff d0 │ call the function at address rax │
│ ret │ c3 │ return from function │
│ syscall │ 0f 05 │ execute a system call │