From 431568faadad8f3f831db9ba1e3fbac7ecab2e50 Mon Sep 17 00:00:00 2001
From: Alexander Medvednikov <alexander@medvednikov.com>
Date: Fri, 29 Nov 2019 12:33:04 +0300
Subject: [PATCH] x64: fix off by one error in for loops

---
 examples/x64/hello_world.v |  6 ++---
 vlib/compiler/x64/gen.v    | 46 +++++++++++++++++++-------------------
 2 files changed, 26 insertions(+), 26 deletions(-)

diff --git a/examples/x64/hello_world.v b/examples/x64/hello_world.v
index 6bda7a20f3..6ebcf145e6 100644
--- a/examples/x64/hello_world.v
+++ b/examples/x64/hello_world.v
@@ -1,6 +1,6 @@
 fn test_fn() {
 	println('test fn')
-}	
+}
 
 fn main() {
 	println('x64 test')
@@ -8,7 +8,7 @@ fn main() {
 		println('Hello world from V x64 machine code generator!')
 	}
 	println('Hello again!')
-	test_fn()
-	println('dne')
+	//test_fn()
+	println('done')
 }
 
diff --git a/vlib/compiler/x64/gen.v b/vlib/compiler/x64/gen.v
index 35016c07c0..699bfa2a88 100644
--- a/vlib/compiler/x64/gen.v
+++ b/vlib/compiler/x64/gen.v
@@ -17,7 +17,7 @@ mut:
 	code_start_pos i64 // location of the start of the assembly instructions
 	fn_addr map[string]i64
 	//string_addr map[string]i64
-}	
+}
 
 enum Register {
 	eax
@@ -35,31 +35,31 @@ enum Size {
 	_16
 	_32
 	_64
-}	
+}
 
 pub fn new_gen(out_name string) &Gen {
 	return &Gen{
 		sect_header_name_pos : 0
 		buf: []
 		out_name: out_name
-	}	
-}	
+	}
+}
 
 pub fn (g &Gen) pos() i64 {
 	return g.buf.len
-}	
+}
 
 
 fn (g mut Gen) write8(n int) {
 	// write 1 byte
 	g.buf << byte(n)
-}	
+}
 
 fn (g mut Gen) write16(n int) {
 	// write 2 bytes
 	g.buf << byte(n)
 	g.buf << byte(n >> 8)
-}	
+}
 
 fn (g mut Gen) write32(n int) {
 	// write 4 bytes
@@ -67,7 +67,7 @@ fn (g mut Gen) write32(n int) {
 	g.buf << byte(n >> 8)
 	g.buf << byte(n >> 16)
 	g.buf << byte(n >> 24)
-}	
+}
 
 fn (g mut Gen) write64(n i64) {
 	// write 8 bytes
@@ -79,7 +79,7 @@ fn (g mut Gen) write64(n i64) {
 	g.buf << byte(n >> 40)
 	g.buf << byte(n >> 48)
 	g.buf << byte(n >> 56)
-}	
+}
 
 fn (g mut Gen) write64_at(n i64, at i64) {
 	// write 8 bytes
@@ -91,12 +91,12 @@ fn (g mut Gen) write64_at(n i64, at i64) {
 	g.buf[at+5] = byte(n >> 40)
 	g.buf[at+6] = byte(n >> 48)
 	g.buf[at+7] = byte(n >> 56)
-}	
+}
 
 fn (g mut Gen) write_string(s string) {
 	for c in s {
 		g.write8(int(c))
-	}	
+	}
 }
 
 fn (g mut Gen) inc(reg Register) {
@@ -104,8 +104,8 @@ fn (g mut Gen) inc(reg Register) {
 	match reg {
 		.r12 { g.write8(0xc4) }
 		else { panic('unhandled inc $reg') }
-	}	
-}	
+	}
+}
 
 fn (g mut Gen) cmp(reg Register, size Size, val i64) {
 	g.write8(0x49)
@@ -114,12 +114,12 @@ fn (g mut Gen) cmp(reg Register, size Size, val i64) {
 		._8 { g.write8(0x83) }
 		._32 { g.write8(0x81) }
 		else { panic('unhandled cmp') }
-	}	
+	}
 	// Third byte depends on the register being compared to
 	match reg {
 		.r12 { g.write8(0xfc) }
 		else { panic('unhandled cmp') }
-	}	
+	}
 	g.write8(int(val))
 }
 
@@ -141,7 +141,7 @@ fn (g mut Gen) jl(addr i64) {
 
 fn (g &Gen) abs_to_rel_addr(addr i64) int {
 	return int(abs(addr - g.buf.len))-1
-}	
+}
 
 fn (g mut Gen) jmp (addr i64) {
 	offset := 0xff - g.abs_to_rel_addr(addr)
@@ -163,7 +163,7 @@ fn (g mut Gen) mov64(reg Register, val i64) {
 fn (g mut Gen) call(addr int) {
 	//rel := g.abs_to_rel_addr(addr)
 	rel := 0xffffffff - int(abs(addr - g.buf.len))-1
-	
+
 	println('call addr=$addr rel_addr=$addr pos=$g.buf.len')
 	g.write8(0xe8)
 	g.write32(addr)
@@ -189,7 +189,7 @@ pub fn (g mut Gen) gen_loop_start(from int) int {
 
 pub fn (g mut Gen) gen_loop_end(to int, label int) {
 	g.cmp(.r12, ._8, to)
-	g.jle(label)
+	g.jl(label)
 }
 
 pub fn (g mut Gen) save_main_fn_addr() {
@@ -206,7 +206,7 @@ pub fn (g mut Gen) gen_print(s string) {
 	g.mov64(.rsi, 0) //segment_start +  0x9f) // str pos // PLACEHOLDER
 	g.mov(.edx, s.len+1) // len
 	g.syscall()
-}	
+}
 
 pub fn (g mut Gen) gen_exit() {
 	// Return 0
@@ -227,11 +227,11 @@ fn (g mut Gen) mov(reg Register, val int) {
 		.r12 {
 			g.write8(0x41)
 			g.write8(0xbc)			// r11 is 0xbb etc
-		}	
+		}
 		else {
 			panic('unhandled mov $reg')
-		}	
-		
+		}
+
 	}
 	g.write32(val)
 }
@@ -245,7 +245,7 @@ pub fn (g mut Gen) register_function_address(name string) {
 pub fn (g mut Gen) call_fn(name string) {
 	if !name.contains('__') {
 		return
-	}	
+	}
 	addr := g.fn_addr[name]
 	g.call(int(addr))
 	println('call $name $addr')