fixed int typ in positive overflow detection

added hello example

examples/hello-name.S

@@ -0,0 +1,103 @@
+jmp entry
+
+puts:
+; Write string to console
+;  r2: [IN] *const u8  String pointer
+;  r3: [IN] usize      String length
+
+    li8     r1, 0x1         ; Write syscall
+    brc     r2, r3, 2       ; Copy parameters
+    li8     r2, 0x1         ; STDOUT
+    eca
+
+    jal     r0, r31, 0
+
+gets:
+; Read string until end of buffer or LF
+;  r2: [IN] *mut u8    Buffer
+;  r3: [IN] usize      Buffer length
+
+    ; Register allocations:
+    ;  r33: *mut u8    Buffer end
+    ;  r34: u8         Immediate char
+    ;  r35: u8         Const [0x0A = LF]
+
+    li8     r35, 0x0A
+    add64   r33, r2, r3
+
+    ; Setup syscall
+    li8     r2, 0x1         ; Stdin
+    cp      r3, r2
+    li8     r4, 0x1         ; Read one char
+
+    jeq     r3, r33, end
+    loop:
+        li8     r1, 0x1     ; Read syscall
+        eca
+        addi64  r3, r3, 1
+        ld      r34, r3, 0, 1
+        jeq     r34, r35, end
+        jne     r3, r33, loop
+    
+    end:
+        ; Set copied amount
+        sub64   r1, r33, r3
+        addi64  r1, r1, -1
+        jal     r0, r31, 0
+
+alloc_pages:
+; Allocate pages
+;  r1: [OUT] *mut u8   Pointer to page
+;  r2: [IN]  u16       Page count
+
+    muli16  r3, r2, 4096    ; page count
+    li8     r1, 0x9         ; mmap syscall
+    li8     r2, 0x0         ; no address set, kernel chosen
+    li8     r4, 0x2         ; PROT_WRITE
+    li8     r5, 0x20        ; MAP_ANONYMOUS
+    li64    r6, -1          ; Doesn't map file
+    li8     r7, 0x0         ; Doesn't map file
+    eca
+
+    jal     r0, r31, 0
+
+entry:
+; Program entrypoint
+
+    ; Register allocations:
+    ; r32: *mut u8     Buffer
+    ; r36: usize       Read buffer length
+
+    ; Allocate one page (4096 KiB)
+    li8     r2, 1
+    jal     r31, r0, alloc_pages
+    cp      r32, r1
+
+    ; Print message
+    lra16   r2, r0, enter_your_name
+    li8     r3, 17
+    jal     r31, r0, puts
+
+    ; Read name
+    cp      r2, r32
+    li16    r3, 4096
+    jal     r31, r0, gets
+    cp      r36, r1
+
+    ; Print your name is
+    lra16   r2, r0, your_name_is
+    li8     r3, 15
+    jal     r31, r0, puts
+
+    ; And now print the name
+    cp      r2, r32
+    cp      r3, r36
+    jal     r31, r0, puts
+
+    tx
+
+
+enter_your_name:
+    .db "Enter your name: "
+your_name_is:
+    .db "\nYour name is: "

examples/hello.S

@@ -1,8 +1,8 @@
-    li8 r1, 1
-    li8 r2, 1
-    lra16 r3, r0, hello_string
-    li8 r4, 0x11
-    eca
+    li8 r1, 1     ; 1->sys::write
+    li8 r2, 1     ; fildes=stdout
+    lra16 r3, r0, hello_string ; buf=hello_string
+    li8 r4, 0x11  ; nbyte=0x11
+    eca ; sys::write(stdout, hello_string, 0x11)
     tx
 hello_string:
     .db "Hello, AbleCorp!\n"

src/directive.c

@@ -8,7 +8,6 @@ AsmError push_string(char *buf, char *input, size_t len) {
             }
             pos += 1;
             chr = input[pos];
-            size_t offset = 1;
             switch (chr) {
                 case '\\':
                     chr = '\\';
@@ -34,16 +33,15 @@ AsmError push_string(char *buf, char *input, size_t len) {
                     }
                     char high = get_hex(input[pos + 1]);
                     char low = get_hex(input[pos + 2]);
-                    offset = 2;
                     if (high > 15 || low > 15) {
                         return ErrStringBadHex;
                     }
+                    pos += 2;
                     chr = high << 4 | low;
                     break;
                 default:
                     return ErrBadStringEscape;
             }
-            pos += offset;
         }
         buf[ndata] = chr;
         ndata += 1;

src/hbas.c

@@ -207,7 +207,7 @@ static AsmError assemble_instr(InstHt ht, char *input, size_t len, Token *tok,
                     return ErrBadNumOverflow;
                 }
                 num_to_write = (uint64_t)tmp;
-            } else if (meta.sign == 2 && (int)num_to_write < 0) {
+            } else if (meta.sign == 2 && (int64_t)num_to_write < 0) {
                 return ErrBadNumOverflow;
             }
             AsmError err = push_int_le(&rv->buf[rv->len], num_to_write,