WASM_X86: Support printing negative integers

integration_tests/print_03.py

@@ -1,7 +1,13 @@
 def Main0():
     x: i32
-    x = (2+3)*5
+    x = (2+3)* (-5)
+    y: i32 = 100
+    z: i32 = 2147483647
+    w: i32 = -2147483648
     print(x)
+    print(y)
+    print(z)
+    print(w)
     print("Hi")
     print("Hello")
     print((5-2) * 7)

src/libasr/codegen/x86_assembler.cpp

@@ -133,6 +133,21 @@ void emit_print_int(X86Assembler &a, const std::string &name)
     X86Reg base = X86Reg::ebp;
     // mov eax, [ebp+8]  // argument "i"
     a.asm_mov_r32_m32(X86Reg::eax, &base, nullptr, 1, 8);
+
+    a.asm_mov_r32_r32(X86Reg::ecx, X86Reg::eax); // make a copy in ecx
+    a.asm_mov_r32_imm32(X86Reg::ebx, 0);
+    a.asm_cmp_r32_r32(X86Reg::eax, X86Reg::ebx);
+    a.asm_jge_label(".print_int_"); // if num >= 0 then print it
+
+    // print "-" and then negate the integer
+    emit_print(a, "string-", 1U);
+    // ecx value changed during print so fetch back
+    a.asm_mov_r32_m32(X86Reg::ecx, &base, nullptr, 1, 8);
+    a.asm_neg_r32(X86Reg::ecx);
+
+    a.add_label(".print_int_");
+
+    a.asm_mov_r32_r32(X86Reg::eax, X86Reg::ecx); // fetch the val in ecx back to eax
     a.asm_xor_r32_r32(X86Reg::esi, X86Reg::esi);
 
     a.add_label(".loop");
@@ -183,6 +198,8 @@ void emit_print_int(X86Assembler &a, const std::string &name)
     a.asm_mov_r32_r32(X86Reg::esp, X86Reg::ebp);
     a.asm_pop_r32(X86Reg::ebp);
     a.asm_ret();
+
+    emit_data_string(a, "string-", "-"); // - symbol for printing negative ints
 }
 
 } // namespace LFortran