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-rw-r--r--04a/Makefile8
-rw-r--r--04a/in04244
2 files changed, 247 insertions, 5 deletions
diff --git a/04a/Makefile b/04a/Makefile
index f6b9915..610b054 100644
--- a/04a/Makefile
+++ b/04a/Makefile
@@ -1,8 +1,6 @@
-all: out03 out04a README.html
-out03: in03 ../03/out02
- ../03/out02
-out04a: out03 in04a
- ./out03 in04a out04a
+all: out04
+out04: in04 ../04/out03
+ ../04/out03
%.html: %.md ../markdown
../markdown $<
clean:
diff --git a/04a/in04 b/04a/in04
index e69de29..1b79464 100644
--- a/04a/in04
+++ b/04a/in04
@@ -0,0 +1,244 @@
+; add 24 + 16 = 40 to the stack pointer to put argc, argv in the right place
+byte 0x48
+byte 0x81
+byte 0xc4
+byte 40
+byte 0
+byte 0
+byte 0
+
+global output_fd
+
+goto main
+
+function main
+ argument argv2
+ argument argv1
+ argument argv0
+ argument argc
+ local input_filename
+ local output_filename
+
+ if argc < 3 goto default_filenames
+ input_filename = argv1
+ output_filename = argv2
+ goto got_filenames
+ :default_filenames
+ input_filename = .str_default_input_filename
+ output_filename = .str_default_output_filename
+ :got_filenames
+
+ output_fd = syscall(2, output_filename, 0x241, 420) ; 420 = octal 644
+ if output_fd >= 0 goto output_file_good
+ file_error(output_filename)
+ :output_file_good
+ exit(0)
+
+:str_default_input_filename
+ string in04a
+ byte 0
+
+:str_default_output_filename
+ string out04a
+ byte 0
+
+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
+
+
+; 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 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 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
+
+function exit
+ argument status_code
+ syscall(0x3c, status_code)
+
+
+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