Execute Brain****/x86 Assembly: Difference between revisions

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 ==x86_64 Assembly==
-{{incorrect|X86_Assembly|This example is not interpreted correctly.<pre>
->++++++++[-<+++++++++>]<.>[][<-]>+>-[+]++>++>+++[>[->+++<<+++>]<<]>-----.
->->+++..+++.>-.<<+[>[+>+]>>]<--------------.>>.+++.------.--------.>+.>+.
-</pre>}}
 GAS Syntax for Linux. Called it "Brainkrieg" after Teen Girl Squad. Operating principle is a little like a multi-cycle processor.
-===Implementation:===
+===Implementation (using jump table):===
 <lang>// Assembly brainf*** interpreter
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 #define STDIN       $0
 #define STDOUT      $1
+#define STDERR      $2
+#define DEBUGMODE   0
 .global _start
@@ Line 104: / Line 102: @@
         cmpq    end, %rbx
         ja      shutdown            // End of code
-        movb    (%rbx), %al
+        movzbq  (%rbx), %rax
         incq    %rbx
         movq    %rbx, inst_ptr
     decode:
-        cmpb    $'+, %al
+        #if DEBUGMODE
-        je      inc_data
+            movb    %al, debugChar
-        cmpb    $'-, %al
+            movq    $1, %rdx
-        je      dec_data
+            movq    $debugChar, %rsi
-        cmpb    $'>, %al
+            movq    STDERR, %rdi
-        je      dp_right
+            movq    SYS_WRITE, %rax
-        cmpb    $'<, %al
+            syscall
-        je      dp_left
+            ERRCHECK    -1
-        cmpb    $'[, %al
+            movzbq  debugChar, %rax
-        je      brf
+        #endif
-        cmpb    $'], %al
+        mov     $branch_table, %rcx
-        je      brb
+        jmp     *(%rcx,%rax,8)
-        cmpb    $'., %al
-        je      out_data
-        cmpb    $',, %al
-        je      in_data
-        jmp     fetch
     // execute:
     dp_left:
@@ Line 138: / Line 131: @@
     dec_data:
         movq    data_ptr, %rbx
-        decq    (%rbx)
+        decb    (%rbx)
         jmp     fetch
     inc_data:
         movq    data_ptr, %rbx
-        incq    (%rbx)
+        incb    (%rbx)
         jmp     fetch
     out_data:
@@ Line 270: / Line 263: @@
 .data
+branch_table:
+    .rept   43
+    .quad   fetch
+    .endr
+    .quad   inc_data
+    .quad   in_data
+    .quad   dec_data
+    .quad   out_data
+    .rept   13
+    .quad   fetch
+    .endr
+    .quad   dp_left
+    .quad   fetch
+    .quad   dp_right
+    .rept   28
+    .quad   fetch
+    .endr
+    .quad   brf
+    .quad   fetch
+    .quad   brb
+    .rept   162
+    .quad   fetch
+    .endr
 brack_smph:    // Bracket matching semaphore
     .quad   0
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 junkChar:       // Also used to check if input was used.
     .byte   0
+#if DEBUGMODE
+debugChar:
+    .byte   0
+#endif
 err_val:
     .byte   0
+// fstat:
 statstruct:     // This struct is 144 bytes. Only want size (+48)
     .zero FSIZEOFF
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     .quad   0
 tape:
-    .zero   30000
+    .zero   (1<<20)
 endtape:
     .zero   1