implement print statement

9 files changed, 39 insertions, 12 deletions

diff --git a/src/back/generator.py b/src/back/generator.py
index 414cf7b..7ca2658 100644
--- a/src/back/generator.py
+++ b/src/back/generator.py
@@ -90,6 +90,14 @@ class Generator(object):
                 elif tac.op == Op.RETURN:
                     self.emit("ADD rv, r0, r%d" % tac.arg1)
                     self.emit(tac)
+                elif tac.op == Op.PRINT:
+                    r = Register().new()
+                    self.emit("PUSH r%d" % tac.arg1)
+                    self.emit("MOV r%d, %d" % (r, 1))
+                    self.emit("PUSH r%d" % r)
+                    self.emit("SYS")
+                    self.emit("POP r0")
+                    self.emit("POP r0")
             elif isinstance(tac, FunctionPrologue):
                 self.generate_prologue(tac.name)
             elif isinstance(tac, FunctionEpilogue):
diff --git a/src/back/tac.py b/src/back/tac.py
index 03303cf..86ccd90 100644
--- a/src/back/tac.py
+++ b/src/back/tac.py
@@ -40,6 +40,8 @@ Op.JMP      = Op("JMP")    # goto x
 Op.CALL     = Op("CALL")   # call x return in y
 Op.RETURN   = Op("RETURN") # return x
 
+Op.PRINT    = Op("PRINT")  # print x
+
 class TAC(object):
     def __init__(self,op,arg1=None,arg2=None):
         self.op = op
diff --git a/src/emu/syscall.c b/src/emu/syscall.c
index 625bbf4..aba3448 100644
--- a/src/emu/syscall.c
+++ b/src/emu/syscall.c
@@ -1,5 +1,6 @@
 #include <unistd.h>
 #include <stdlib.h>
+#include <inttypes.h>
 
 #include "cpu.h"
 #include "mem.h"
@@ -13,11 +14,8 @@ void do_syscall(void)
 	case SYS_exit:
 		exit(arg(1));
 		break;
-	case SYS_read:
-		push(read(arg(1), &MEM[arg(2)], arg(3)));
-		break;
-	case SYS_write:
-		push(write(arg(1), &MEM[arg(2)], arg(3)));
+	case SYS_print:
+		printf("%"PRIu32"\n", arg(1));
 		break;
 	default:
 		push(-1);
diff --git a/src/emu/syscall.h b/src/emu/syscall.h
index 7c7265c..afd3e9d 100644
--- a/src/emu/syscall.h
+++ b/src/emu/syscall.h
@@ -2,14 +2,11 @@
 #define _SYSCALL_H
 
 /* calling convention:
- * - pass syscall number in GPR[1]
- * - pass arguments in GPR[2]-GPR[9]
- * - return code is passed in GPR[2]
+ * - syscall number and params are passed on stack
  */
 
 #define SYS_exit  0x00
-#define SYS_read  0x01
-#define SYS_write 0x02
+#define SYS_print 0x01
 
 void do_syscall(void);
 
diff --git a/src/front/ast.py b/src/front/ast.py
index 77aab95..f272ca2 100644
--- a/src/front/ast.py
+++ b/src/front/ast.py
@@ -149,6 +149,18 @@ class ReturnStatement(Statement):
     def __repr__(self):
         return "<ReturnStatement at line %d>" % self.lineno
 
+class PrintStatement(Statement):
+    def __init__(self, expression, lineno = -1):
+        self.expression = expression
+        self.lineno = lineno
+
+    def generate(self, before, after, last):
+        self.debug("PrintStatement.generate(before = %d, after = %d): %s" % (before, after, repr(self)))
+        self.emit(Op.PRINT, self.expression.reduce(), last)
+
+    def __repr__(self):
+        return "<PrintStatement at line %d>" % self.lineno
+
 class AssignStatement(Statement):
     def __init__(self, ident, expression, lineno = -1):
         self.ident = ident
diff --git a/src/front/lexer.py b/src/front/lexer.py
index e6eb172..dcaa672 100644
--- a/src/front/lexer.py
+++ b/src/front/lexer.py
@@ -22,6 +22,7 @@ class Lexer:
                               'if': Token(Tag.IF),
                               'else': Token(Tag.ELSE),
                               'call': Token(Tag.CALL),
+                              'print': Token(Tag.PRINT),
                               'fun': Token(Tag.FUN),
                               'end': Token(Tag.END)}
         return
diff --git a/src/front/parser.py b/src/front/parser.py
index 72e0051..5029158 100644
--- a/src/front/parser.py
+++ b/src/front/parser.py
@@ -149,12 +149,13 @@ class Parser:
         self.match(Tag.END, Tag.NEWLINE)
         return Function(name, args, block, line)
 
-    # statement = ( if_statement | while_statement | assign_statement | return_statement | function_call ) nl.
+    # statement = ( if_statement | while_statement | assign_statement | return_statement | function_call | print_statement ) nl.
     def statement(self):
         res =  {Tag.IF:         self.if_statement,
                 Tag.WHILE:      self.while_statement,
                 Tag.IDENT:      self.assignment,
                 Tag.RETURN:     self.return_statement,
+                Tag.PRINT:      self.print_statement,
                 Tag.CALL:       self.function_call,
                 }[self.token.tag]()
         self.match(Tag.NEWLINE)
@@ -201,6 +202,12 @@ class Parser:
         self.scope.add_locals(name)
         return AssignStatement(name, exp, line)
 
+    def print_statement(self):
+        line = self.lexer.line
+        self.match(Tag.PRINT)
+        exp = self.boolean()
+        return PrintStatement(exp, line)
+
     # program = function_list.
     def program(self):
         return Program(self.function_list())
diff --git a/src/front/token.py b/src/front/token.py
index 78e9dab..d0970f3 100644
--- a/src/front/token.py
+++ b/src/front/token.py
@@ -26,6 +26,7 @@ Tag.LPAREN      = Tag("LPAREN")
 Tag.RPAREN      = Tag("RPAREN")
 Tag.NEWLINE     = Tag("NEWLINE")
 Tag.COMMA       = Tag("COMMA")
+Tag.PRINT       = Tag("PRINT")
 Tag.FUN         = Tag("FUN")
 Tag.CALL        = Tag("CALL")
 Tag.ASSIGNMENT  = Tag("ASSIGNMENT")
diff --git a/test/test1.t b/test/test1.t
index af9d688..12580bd 100644
--- a/test/test1.t
+++ b/test/test1.t
@@ -13,5 +13,6 @@ fun main[]
 		sum = sum + call fib[i]
 		i = i + 1
 	end
-	@sum
+	print sum
+	@0
 end