Fixed memory lea issue in stage 4

Added Stage 5 polygon and array functions

stage4/bootasm2.S

@@ -275,14 +275,14 @@ cons_filled_rect_check_x_dir:
     cmpw    $0, %ax
     jge     cons_filled_rect_check_y_dir
     add     %ax, rectx(%bp)
-    neg     rectwidth(%bp)
+    negw    rectwidth(%bp)
 
 cons_filled_rect_check_y_dir:
     movw    rectheight(%bp), %ax            # Check if the user has entered a negative height value and swap the direction to a pos
     cmpw    $0, %ax
     jge     cons_filled_rect_check_x_zero
     add     %ax, recty(%bp)
-    neg     rectheight(%bp)    
+    negw    rectheight(%bp)    
 
 cons_filled_rect_check_x_zero:
     movw    rectx(%bp), %ax                 # Check if the x value is a negative value, set it to 0 and figure out the offset so we
@@ -344,8 +344,7 @@ cons_filled_rect_setup:
     movw    (screen_width), %ax          # Set ax to 320 so that we can multiply this by y   
     mul     %dx                          # does the (y * 320) part of our math            
     add     rectx(%bp), %ax              # Add the value of x to register ax
-    movw    %ax, %si
+    movw    %ax, %bx                     # Load the memory offset address into the bx register    
-    lea     %es:(%si), %bx      # Load the memory address into the bx register
     
     movw    rectheight(%bp), %si    # Set the counter to our height which should be the number of lines to draw to
 

stage5/.vscode/tasks.json

@@ -0,0 +1,19 @@
+{
+    // See https://go.microsoft.com/fwlink/?LinkId=733558
+    // for the documentation about the tasks.json format
+    "version": "2.0.0",
+    "tasks": [
+        {
+            "label": "Build and QEMU",
+            "type": "shell",
+            "command": "make qemu",
+            "problemMatcher": []
+        },
+        {
+            "label": "Build and QEMU (debug)",
+            "type": "shell",
+            "command": "make qemu-gdb",
+            "problemMatcher": []
+        }
+    ]
+}

stage5/Makefile

@@ -0,0 +1,102 @@
+# Try to infer the correct TOOLPREFIX if not set
+ifndef TOOLPREFIX
+TOOLPREFIX := $(shell if i386-jos-elf-objdump -i 2>&1 | grep '^elf32-i386$$' >/dev/null 2>&1; \
+	then echo 'i386-jos-elf-'; \
+	elif objdump -i 2>&1 | grep 'elf32-i386' >/dev/null 2>&1; \
+	then echo ''; \
+	else echo "***" 1>&2; \
+	echo "*** Error: Couldn't find an i386-*-elf version of GCC/binutils." 1>&2; \
+	echo "*** Is the directory with i386-jos-elf-gcc in your PATH?" 1>&2; \
+	echo "*** If your i386-*-elf toolchain is installed with a command" 1>&2; \
+	echo "*** prefix other than 'i386-jos-elf-', set your TOOLPREFIX" 1>&2; \
+	echo "*** environment variable to that prefix and run 'make' again." 1>&2; \
+	echo "*** To turn off this error, run 'gmake TOOLPREFIX= ...'." 1>&2; \
+	echo "***" 1>&2; exit 1; fi)
+endif
+
+# If the makefile can't find QEMU, specify its path here
+# QEMU = qemu-system-i386
+
+# Try to infer the correct QEMU
+ifndef QEMU
+QEMU = $(shell if which qemu > /dev/null; \
+	then echo qemu; exit; \
+	elif which qemu-system-i386 > /dev/null; \
+	then echo qemu-system-i386; exit; \
+	elif which qemu-system-x86_64 > /dev/null; \
+	then echo qemu-system-x86_64; exit; \
+	else \
+	qemu=/Applications/Q.app/Contents/MacOS/i386-softmmu.app/Contents/MacOS/i386-softmmu; \
+	if test -x $$qemu; then echo $$qemu; exit; fi; fi; \
+	echo "***" 1>&2; \
+	echo "*** Error: Couldn't find a working QEMU executable." 1>&2; \
+	echo "*** Is the directory containing the qemu binary in your PATH" 1>&2; \
+	echo "*** or have you tried setting the QEMU variable in Makefile?" 1>&2; \
+	echo "***" 1>&2; exit 1)
+endif
+
+CC = $(TOOLPREFIX)gcc
+AS = $(TOOLPREFIX)gas
+LD = $(TOOLPREFIX)ld
+OBJCOPY = $(TOOLPREFIX)objcopy
+OBJDUMP = $(TOOLPREFIX)objdump
+CFLAGS = -fno-pic -static -fno-builtin -fno-strict-aliasing -O2 -Wall -MD -ggdb -m32 -Werror -fno-omit-frame-pointer
+CFLAGS += $(shell $(CC) -fno-stack-protector -E -x c /dev/null >/dev/null 2>&1 && echo -fno-stack-protector)
+ASFLAGS = -m32 -gdwarf-2 -Wa,-divide
+# FreeBSD ld wants ``elf_i386_fbsd''
+LDFLAGS += -m $(shell $(LD) -V | grep elf_i386 2>/dev/null | head -n 1)
+
+# Disable PIE when possible (for Ubuntu 16.10 toolchain)
+ifneq ($(shell $(CC) -dumpspecs 2>/dev/null | grep -e '[^f]no-pie'),)
+CFLAGS += -fno-pie -no-pie
+endif
+ifneq ($(shell $(CC) -dumpspecs 2>/dev/null | grep -e '[^f]nopie'),)
+CFLAGS += -fno-pie -nopie
+endif
+
+xv6.img: bootblock bootblock2
+	dd if=/dev/zero of=xv6.img count=10000
+	dd if=bootblock of=xv6.img conv=notrunc
+	dd if=bootblock2 of=xv6.img seek=1 conv=notrunc
+
+bootblock: bootasm.S 
+	$(CC) $(CFLAGS) -fno-pic -nostdinc -I. -c bootasm.S
+	$(LD) $(LDFLAGS) -N -e start -Ttext 0x7C00 -o bootblock.o bootasm.o 
+	$(OBJCOPY) -S -O binary -j .text bootblock.o bootblock
+	./sign.pl bootblock
+
+bootblock2: bootasm2.S
+	$(CC) $(CFLAGS) -fno-pic -nostdinc -I. -c bootasm2.S
+	$(LD) $(LDFLAGS) -N -e start -Ttext 0x9000 -o bootblock2.o bootasm2.o 
+	$(OBJCOPY) -S -O binary -j .text bootblock2.o bootblock2
+
+
+.PRECIOUS: %.o
+
+clean: 
+	rm -f *.tex *.dvi *.idx *.aux *.log *.ind *.ilg \
+	*.o *.d *.asm *.sym vectors.S bootblock bootblock2 entryother \
+	initcode initcode.out kernel xv6.img fs.img kernelmemfs \
+	xv6memfs.img mkfs \
+	syscall.h syscalltable.h usys.S 
+
+# run in emulators
+
+# try to generate a unique GDB port
+GDBPORT = $(shell expr `id -u` % 5000 + 25000)
+# QEMU's gdb stub command line changed in 0.11
+QEMUGDB = $(shell if $(QEMU) -help | grep -q '^-gdb'; \
+	then echo "-gdb tcp::$(GDBPORT)"; \
+	else echo "-s -p $(GDBPORT)"; fi)
+ifndef CPUS
+CPUS := 1
+endif
+QEMUOPTS = -drive file=xv6.img,index=0,media=disk,format=raw -smp $(CPUS) -m 512 $(QEMUEXTRA)
+
+qemu: xv6.img
+	$(QEMU) -vga std -serial mon:stdio $(QEMUOPTS)
+
+qemu-gdb: xv6.img 
+	@echo "*** Now run 'gdb'." 1>&2
+	$(QEMU) -vga std -serial mon:stdio $(QEMUOPTS) -S -gdb tcp::1234
+

stage5/bootasm.S

@@ -0,0 +1,101 @@
+# When the PC starts, the processor is essentially emulating an 8086 processor, i.e. 
+# a 16-bit processor.  So our initial boot loader code is 16-bit code that will 
+# eventually switch the processor into 32-bit mode.
+
+# This code is linked to assume a starting address of 0x7C00 which is where the BIOS
+# will load a boot segment.
+
+.code16                         # Assemble for 16-bit mode
+.globl start
+start:
+    jmp     real_start
+
+# Write to the console using BIOS.
+# 
+# Input: SI contains the address of the null-terminated string to be displayed
+
+cons_write:
+    movb    $0x0e, %ah           # 0x0e is the INT 10h BIOS call to output the value contained in AL to screen
+
+cons_write_rpt:
+    movb    (%si), %al          # Load the byte at the location contained in the SI register into AL   
+    inc     %si                 # Add 1 to the value in SI
+    cmp     $0, %al             # Compare the value in AL with 0
+    jz      cons_write_done     # If it is zero, then we are done
+    int     $0x10               # Output the character in AL to the screen
+    jmp     cons_write_rpt      # and continue
+
+cons_write_done:                # Something that is called will never return 
+    ret                         # until a 'ret' instruction is encountered.  Labels do 
+                                # not give a program any structure.  They just give a 
+                                # memory location a name that we can use in our code. 
+
+cons_write_crlf:
+    movb    $0x0e, %ah          # Output CR
+    movb    $0x0d, %al
+    int     $0x10
+    movb    $0x0a, %al          # Output LF
+    int     $0x10
+    ret
+
+cons_writeline:
+    call    cons_write
+    call    cons_write_crlf
+    ret    
+
+real_start:
+    cli                         # BIOS enabled interrupts; disable
+
+    # Zero data segment registers DS, ES, and SS.
+    xorw    %ax, %ax            # Set %ax to zero
+    movw    %ax, %ds            # -> Data Segment
+    movw    %ax, %es            # -> Extra Segment
+    movw    %ax, %ss            # -> Stack Segment
+    movw    $0, %sp             # Set the stack to the top of the segment
+
+    movb    %dl, (boot_device) # Boot device number is passed in DL from BIOS. Save it hear since DL might get trashed
+
+    movw    $boot_message, %si  # Display our boot message
+    call    cons_writeline
+
+	movb	$2, %ah				# BIOS function 13h, sub-function 2 is read sectors
+	movb	$7, %al				# Number of sectors to read = 7
+	movw	$0x9000, %bx		# The 7 sectors will be loaded into memory at ES:BX (0000:9000h)
+	movb	$0, %ch				# Use cylinder 0
+	movb 	$0, %dh 			# Use head 0
+	movb	(boot_device), %dl  # Retrieve the ID of our boot device			
+	movb 	$2, %cl				# Start reading at sector 2 (i.e. one after the boot sector)
+	int 	$0x13
+	cmpb	$7, %al				# AL returns the number of sectors read.  If this is not 7, report an error
+	jne		read_failed
+
+    movb    (0x9000), %al     # Check that what we loaded is not empty
+    cmpb    $0, %al
+    je      read_failed
+
+	movb	(boot_device), %dl	# Pass boot device ID to second stage
+    movw    $0x9000, %ax        # Jump to stage 2
+    jmp     *%ax
+
+read_failed:	                # Display error messages
+	movw 	$read_failed_msg, %si
+    call    cons_writeline
+	
+	mov 	$cannot_continue, %si	
+    call    cons_writeline
+	
+endless_loop:                   # Loop forever more
+    jmp     endless_loop    
+
+# Program data
+
+boot_device:
+    .byte   0
+
+boot_message:     
+    .string "Boot Loader V1.0"             
+read_failed_msg:
+    .string "Unable to read stage 2 of the boot process"
+cannot_continue:
+    .string "Cannot continue boot process"
+

stage5/bootasm.d

@@ -0,0 +1 @@
+bootasm.o: bootasm.S

stage5/bootasm2.d

@@ -0,0 +1 @@
+bootasm2.o: bootasm2.S

stage5/sign.pl

@@ -0,0 +1,19 @@
+#!/usr/bin/perl
+
+open(SIG, $ARGV[0]) || die "open $ARGV[0]: $!";
+
+$n = sysread(SIG, $buf, 1000);
+
+if($n > 510){
+  print STDERR "boot block too large: $n bytes (max 510)\n";
+  exit 1;
+}
+
+print STDERR "boot block is $n bytes (max 510)\n";
+
+$buf .= "\0" x (510-$n);
+$buf .= "\x55\xAA";
+
+open(SIG, ">$ARGV[0]") || die "open >$ARGV[0]: $!";
+print SIG $buf;
+close SIG;