start C compiler

05/util.b

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+
+function file_error
+	argument name
+	fputs(2, .str_file_error)
+	fputs(2, name)
+	fputc(2, 10)
+	exit(1)
+	
+:str_file_error
+	string Error opening file:
+	byte 32
+	byte 0
+
+function malloc
+	argument size
+	local total_size
+	local memory
+	total_size = size + 8
+	memory = syscall(9, 0, total_size, 3, 0x22, -1, 0)
+	if memory ] 0xffffffffffff0000 goto malloc_failed
+	*8memory = total_size
+	return memory + 8
+
+:malloc_failed
+	fputs(2, .str_out_of_memory)
+	exit(1)
+	
+:str_out_of_memory
+	string Out of memory.
+	byte 10
+	byte 0
+
+function free
+	argument memory
+	local psize
+	local size
+	psize = memory - 8
+	size = *8psize
+	syscall(11, psize, size)
+	return
+
+; returns a pointer to a null-terminated string containing the number given
+function itos
+	global 32 itos_string
+	argument x
+	local c
+	local p
+	p = &itos_string
+	p += 30
+	:itos_loop
+		c = x % 10
+		c += '0
+		*1p = c
+		x /= 10
+		if x == 0 goto itos_loop_end
+		p -= 1
+		goto itos_loop
+	:itos_loop_end
+	return p
+
+
+; returns the number at the start of the given string
+function stoi
+	argument s
+	local p
+	local n
+	local c
+	n = 0
+	p = s
+	:stoi_loop
+		c = *1p
+		if c < '0 goto stoi_loop_end
+		if c > '9 goto stoi_loop_end
+		n *= 10
+		n += c - '0
+		p += 1
+		goto stoi_loop
+	:stoi_loop_end
+	return n
+
+function memchr
+	argument mem
+	argument c
+	local p
+	local a
+	p = mem
+	:memchr_loop
+		a = *1p
+		if a == c goto memchr_loop_end
+		p += 1
+		goto memchr_loop
+	:memchr_loop_end
+	return p
+
+function strlen
+	argument s
+	local c
+	local p
+	p = s
+	:strlen_loop
+		c = *1p
+		if c == 0 goto strlen_loop_end
+		p += 1
+		goto strlen_loop
+	:strlen_loop_end
+	return p - s
+
+function strcpy
+	argument dest
+	argument src
+	local p
+	local q
+	local c
+	p = dest
+	q = src
+	:strcpy_loop
+		c = *1q
+		*1p = c
+		if c == 0 goto strcpy_loop_end
+		p += 1
+		q += 1
+		goto strcpy_loop
+	:strcpy_loop_end
+	return p
+	
+function str_startswith
+	argument s
+	argument prefix
+	local p
+	local q
+	local c1
+	local c2
+	p = s
+	q = prefix
+	:str_startswith_loop
+		c1 = *1p
+		c2 = *1q
+		if c2 == 0 goto return_1
+		if c1 != c2 goto return_0
+		p += 1
+		q += 1
+		goto str_startswith_loop
+
+function fputs
+	argument fd
+	argument s
+	local length
+	length = strlen(s)
+	syscall(1, fd, s, length)
+	return
+
+function puts
+	argument s
+	fputs(1, s)
+	return
+
+function fputn
+	argument fd
+	argument n
+	local s
+	s = itos(n)
+	fputs(fd, s)
+	return
+
+function fputc
+	argument fd
+	argument c
+	local p
+	p = &c
+	syscall(1, fd, p, 1)
+	return
+
+function putc
+	argument c
+	fputc(1, c)
+	return
+
+; returns 0 at end of file
+function fgetc
+	argument fd
+	local c
+	local p
+	c = 0
+	p = &c
+	syscall(0, fd, p, 1)
+	return c
+
+; read a line from fd as a null-terminated string
+; returns 0 at end of file, 1 otherwise
+function fgets
+	argument fd
+	argument buf
+	argument size
+	local p
+	local end
+	local c
+	p = buf
+	end = buf + size
+	
+	:fgets_loop
+		c = fgetc(fd)
+		if c == 0 goto fgets_eof
+		if c == 10 goto fgets_eol
+		*1p = c
+		p += 1
+		if p == end goto fgets_eob
+		goto fgets_loop
+		
+	:fgets_eol ; end of line
+	*1p = 0
+	return 1
+	:fgets_eof ; end of file
+	*1p = 0
+	return 0
+	:fgets_eob ; end of buffer
+	p -= 1
+	*1p = 0
+	return 1
+
+; open the given file for reading
+function open_r
+	argument filename
+	local fd
+	fd = syscall(2, filename, 0)
+	if fd < 0 goto open_r_error
+		return fd
+	:open_r_error
+		file_error(filename)
+		return -1
+
+; open the given file for writing with the given mode
+function open_w
+	argument filename
+	argument mode
+	local fd
+	fd = syscall(2, filename, 0x241, mode)
+	if fd < 0 goto open_w_error
+		return fd
+	:open_w_error
+		file_error(filename)
+		return -1
+	
+function close
+	argument fd
+	syscall(3, fd)
+	return
+
+function isupper
+	argument c
+	if c < 'A goto return_0
+	if c <= 'Z goto return_1
+	goto return_0
+
+function exit
+	argument status_code
+	syscall(0x3c, status_code)
+
+:return_0
+	return 0
+:return_1
+	return 1
+
+function syscall
+	; I've done some testing, and this should be okay even if
+	; rbp-56 goes beyond the end of the stack.
+	; mov rax, [rbp-16]
+	byte 0x48
+	byte 0x8b
+	byte 0x85
+	byte 0xf0
+	byte 0xff
+	byte 0xff
+	byte 0xff
+	; mov rdi, rax
+	byte 0x48
+	byte 0x89
+	byte 0xc7
+	
+	; mov rax, [rbp-24]
+	byte 0x48
+	byte 0x8b
+	byte 0x85
+	byte 0xe8
+	byte 0xff
+	byte 0xff
+	byte 0xff
+	; mov rsi, rax
+	byte 0x48
+	byte 0x89
+	byte 0xc6
+	
+	; mov rax, [rbp-32]
+	byte 0x48
+	byte 0x8b
+	byte 0x85
+	byte 0xe0
+	byte 0xff
+	byte 0xff
+	byte 0xff
+	; mov rdx, rax
+	byte 0x48
+	byte 0x89
+	byte 0xc2
+	
+	; mov rax, [rbp-40]
+	byte 0x48
+	byte 0x8b
+	byte 0x85
+	byte 0xd8
+	byte 0xff
+	byte 0xff
+	byte 0xff
+	; mov r10, rax
+	byte 0x49
+	byte 0x89
+	byte 0xc2
+	
+	; mov rax, [rbp-48]
+	byte 0x48
+	byte 0x8b
+	byte 0x85
+	byte 0xd0
+	byte 0xff
+	byte 0xff
+	byte 0xff
+	; mov r8, rax
+	byte 0x49
+	byte 0x89
+	byte 0xc0
+	
+	; mov rax, [rbp-56]
+	byte 0x48
+	byte 0x8b
+	byte 0x85
+	byte 0xc8
+	byte 0xff
+	byte 0xff
+	byte 0xff
+	; mov r9, rax
+	byte 0x49
+	byte 0x89
+	byte 0xc1
+	
+	; mov rax, [rbp-8]
+	byte 0x48
+	byte 0x8b
+	byte 0x85
+	byte 0xf8
+	byte 0xff
+	byte 0xff
+	byte 0xff
+	
+	; syscall
+	byte 0x0f
+	byte 0x05
+	
+	return