native: integer-to-string conversion (#14758)

Author: Spydr06

vlib/v/gen/native/amd64.v

@@ -59,12 +59,9 @@ fn byt(n int, s int) u8 {
 }
 
 fn (mut g Gen) inc(reg Register) {
-	g.write16(0xff49)
-	match reg {
-		.rcx { g.write8(0xc1) }
-		.r12 { g.write8(0xc4) }
-		else { panic('unhandled inc $reg') }
-	}
+	g.write8(0x48)
+	g.write8(0xff)
+	g.write8(0xc0 + int(reg))
 	g.println('inc $reg')
 }
 
@@ -138,6 +135,16 @@ fn (mut g Gen) cmp_reg(reg Register, reg2 Register) {
 				}
 			}
 		}
+		.rdi {
+			match reg2 {
+				.rsi {
+					g.write([u8(0x48), 0x39, 0xf7])
+				}
+				else {
+					g.n_error('Cannot compare $reg and $reg2')
+				}
+			}
+		}
 		else {
 			g.n_error('Cannot compare $reg and $reg2')
 		}
@@ -235,14 +242,14 @@ fn abs(a i64) i64 {
 fn (mut g Gen) tmp_jle(addr i64) {
 	// Calculate the relative offset to jump to
 	// (`addr` is absolute address)
-	offset := 0xff - int(abs(addr - g.buf.len)) - 1
+	offset := 0xff - g.abs_to_rel_addr(addr)
 	g.write8(0x7e)
 	g.write8(offset)
 	g.println('jle')
 }
 
 fn (mut g Gen) jl(addr i64) {
-	offset := 0xff - int(abs(addr - g.buf.len)) - 1
+	offset := 0xff - g.abs_to_rel_addr(addr)
 	g.write8(0x7c)
 	g.write8(offset)
 	g.println('jl')
@@ -381,7 +388,7 @@ fn (mut g Gen) mov_int_to_var(var_offset int, size Size, integer int) {
 
 fn (mut g Gen) lea_var_to_reg(reg Register, var_offset int) {
 	match reg {
-		.rax, .rbx, .rsi {
+		.rax, .rbx, .rsi, .rdi {
 			g.write8(0x48)
 		}
 		else {}
@@ -445,6 +452,11 @@ fn (mut g Gen) syscall() {
 	g.println('syscall')
 }
 
+fn (mut g Gen) cdq() {
+	g.write8(0x99)
+	g.println('cdq')
+}
+
 pub fn (mut g Gen) ret() {
 	g.write8(0xc3)
 	g.println('ret')
@@ -509,8 +521,7 @@ pub fn (mut g Gen) add(reg Register, val int) {
 pub fn (mut g Gen) add8(reg Register, val int) {
 	g.write8(0x48)
 	g.write8(0x83)
-	// g.write8(0xe8 + reg) // TODO rax is different?
-	g.write8(0xc4)
+	g.write8(0xc0 + int(reg))
 	g.write8(val)
 	g.println('add8 $reg,$val.hex2()')
 }
@@ -595,9 +606,18 @@ pub fn (mut g Gen) rep_stosb() {
 	g.println('rep stosb')
 }
 
-pub fn (mut g Gen) cld_repne_scasb() {
+pub fn (mut g Gen) std() {
+	g.write8(0xfd)
+	g.println('std')
+}
+
+pub fn (mut g Gen) cld() {
 	g.write8(0xfc)
 	g.println('cld')
+}
+
+pub fn (mut g Gen) cld_repne_scasb() {
+	g.cld()
 	g.write8(0xf2)
 	g.write8(0xae)
 	g.println('repne scasb')
@@ -931,6 +951,9 @@ fn (mut g Gen) mov(reg Register, val int) {
 				g.write8(0x41)
 				g.write8(0xbc) // r11 is 0xbb etc
 			}
+			.rbx {
+				g.write8(0xbb)
+			}
 			else {
 				g.n_error('unhandled mov $reg')
 			}
@@ -1084,6 +1107,18 @@ fn (mut g Gen) mov_reg(a Register, b Register) {
 		g.write8(0x48)
 		g.write8(0x89)
 		g.write8(0xc7)
+	} else if a == .r12 && b == .rdi {
+		g.write8(0x49)
+		g.write8(0x89)
+		g.write8(0xfc)
+	} else if a == .rdi && b == .r12 {
+		g.write8(0x4c)
+		g.write8(0x89)
+		g.write8(0xe7)
+	} else if a == .rsi && b == .rdi {
+		g.write8(0x48)
+		g.write8(0x89)
+		g.write8(0xfe)
 	} else {
 		g.n_error('unhandled mov_reg combination for $a $b')
 	}
@@ -1988,6 +2023,9 @@ fn (mut g Gen) convert_int_to_string(r Register, buffer int) {
 	g.labels.addrs[skip_zero_label] = g.pos()
 	g.println('; label $skip_zero_label')
 
+	// load a pointer to the string to rdi
+	g.lea_var_to_reg(.rdi, buffer)
+
 	// detect if value in rax is negative
 	g.cmp_zero(.rax)
 	skip_minus_label := g.labels.new_label()
@@ -2000,11 +2038,103 @@ fn (mut g Gen) convert_int_to_string(r Register, buffer int) {
 
 	// add a `-` sign as the first character
 	g.mov_int_to_var(buffer, ._8, '-'[0])
-	g.neg(.rax)
+	g.neg(.rax) // negate our integer to make it positive
+	g.inc(.rdi) // increment rdi to skip the `-` character
 	g.labels.addrs[skip_minus_label] = g.pos()
+	g.println('; label $skip_minus_label')
+
+	g.mov_reg(.r12, .rdi) // copy the buffer position to rcx
+
+	loop_label := g.labels.new_label()
+	loop_start := g.pos()
+	g.println('; label $loop_label')
+
+	g.push(.rax)
+
+	g.mov(.rdx, 0)
+	g.mov(.rbx, 10)
+	g.div_reg(.rax, .rbx)
+	g.add8(.rdx, '0'[0])
 
-	// TODO: convert non-zero integer to string
+	g.write8(0x66)
+	g.write8(0x89)
+	g.write8(0x17)
+	g.println('mov BYTE PTR [rdi], rdx')
+
+	// divide the integer in rax by 10 for next iteration
+	g.pop(.rax)
+	g.mov(.rbx, 10)
+	g.cdq()
+	g.write8(0x48)
+	g.write8(0xf7)
+	g.write8(0xfb)
+	g.println('idiv rbx')
+
+	// go to the next character
+	g.inc(.rdi)
+
+	// if the number in rax still isn't zero, repeat
+	g.cmp_zero(.rax)
+	loop_cjmp_addr := g.cjmp(.jg)
+	g.labels.patches << LabelPatch{
+		id: loop_label
+		pos: loop_cjmp_addr
+	}
+	g.println('; jump to label $skip_minus_label')
+	g.labels.addrs[loop_label] = loop_start
+
+	// after all was converted, reverse the string
+	g.reverse_string(.r12)
 
 	g.labels.addrs[end_label] = g.pos()
 	g.println('; label $end_label')
 }
+
+fn (mut g Gen) reverse_string(reg Register) {
+	if reg != .rdi {
+		g.mov_reg(.rdi, reg)
+	}
+
+	g.mov(.eax, 0)
+
+	g.write8(0x48)
+	g.write8(0x8d)
+	g.write8(0x48)
+	g.write8(0xff)
+	g.println('lea rcx, [rax-0x1]')
+
+	g.mov_reg(.rsi, .rdi)
+
+	g.write8(0xf2)
+	g.write8(0xae)
+	g.println('repnz scas al, BYTE PTR es:[rdi]')
+
+	g.sub8(.rdi, 0x2)
+	g.cmp_reg(.rdi, .rsi)
+
+	g.write8(0x7e)
+	g.write8(0x0a)
+	g.println('jle 0x1e')
+
+	g.write8(0x86)
+	g.write8(0x07)
+	g.println('xchg BYTE PTR [rdi], al')
+
+	g.write8(0x86)
+	g.write8(0x06)
+	g.println('xchg BYTE PTR [rsi], al')
+
+	g.std()
+
+	g.write8(0xaa)
+	g.println('stos BYTE PTR es:[rdi], al')
+
+	g.cld()
+
+	g.write8(0xac)
+	g.println('lods al, BYTE PTR ds:[rsi]')
+
+	g.write8(0xeb)
+	g.write8(0xf1)
+	g.println('jmp 0xf')
+}

vlib/v/gen/native/tests/print.vv

@@ -33,8 +33,17 @@ fn test_idents() {
 	x := 0
 	println(x)
 
-	// y := -5
-	// println(y)
+	y := 5
+	println(y)
+
+	z := -8
+	println(z)
+
+	a := 123
+	println(a)
+
+	b := -456
+	println(b)
 }
 
 fn main() {

vlib/v/gen/native/tests/print.vv.out

@@ -4,3 +4,7 @@ Hello World
 4
 8
 0
+5
+-8
+123
+-456