Added stage 2 of the assessment with stack management
Changed Stage 1 to use full registers and the si register instead of splitting them
This commit is contained in:
iDunnoDev
1
.gitattributes
vendored
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1
.gitattributes
vendored
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@ -0,0 +1 @@
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*.img filter=lfs diff=lfs merge=lfs -text
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@ -39,7 +39,6 @@ cons_writeline:
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ret
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ret
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# Added Write Hex and Int functions to help with debugging
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# Added Write Hex and Int functions to help with debugging
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HexChars: .ascii "0123456789ABCDEF"
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HexChars: .ascii "0123456789ABCDEF"
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cons_write_hex:
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cons_write_hex:
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@ -62,7 +61,7 @@ cons_write_int:
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cmpw $0, %ax
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cmpw $0, %ax
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jge getdigit
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jge getdigit
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xor %ax, %ax
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xor %ax, %ax # Added to handle signed numbers, it adds the minus and then neg's the number
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movb $0x0E, %ah
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movb $0x0E, %ah
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movb $0x2D, %al
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movb $0x2D, %al
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int $0x10
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int $0x10
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@ -85,13 +84,14 @@ getdigit:
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IntBuffer: .string " "
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IntBuffer: .string " "
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# Draw Line function
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cons_draw_line:
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cons_draw_line:
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movw $0, err # Make sure that err starts at 0
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movw $0, err # Make sure that err starts at 0
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movw %ax, (x0) # Move the initial vars from the registers to static memory
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movw %ax, (x0) # Move the initial vars from the registers to static memory
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movb %cl, (y0)
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movw %bx, (y0)
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movw %bx, (x1)
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movw %cx, (x1)
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movb %ch, (y1)
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movw %dx, (y1)
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movb %dl, (color)
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movw %si, (color)
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movw x1, %cx # Load x1 and y1 into the registers
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movw x1, %cx # Load x1 and y1 into the registers
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movw y1, %dx
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movw y1, %dx
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@ -102,16 +102,17 @@ cons_draw_line:
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cons_line_check_x:
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cons_line_check_x:
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movw x0, %cx # Load x0 into register cx so we can manipulate this value to plot each pixel
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movw x0, %cx # Load x0 into register cx so we can manipulate this value to plot each pixel
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movw $1, (sx) # Preload x slope with 1
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movw $1, (sx) # Preload the x slope with 1
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cmp x1, %cx # Check if x1 is less than x0 and we can move to y
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cmp x1, %cx # Check if x0 is less than x1 and we can move to y
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jl cons_line_check_y
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jl cons_line_check_y
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negw sx # if x1 is greater than we need to flip the slope and the x delta values
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negw sx # If x1 is greater than we need to flip the slope and the x delta values
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negw deltax
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negw deltax # Flipping the deltax here saves us from having to have an abs function because if
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# x0 was greater than x1 we know we have a negative delta value and we flip it to pos
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cons_line_check_y:
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cons_line_check_y:
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movw y0, %dx # Load y0 into register dx so we can manipulate this value to plot each pixel
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movw y0, %dx # Load y0 into register dx so we can manipulate this value to plot each pixel
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movw $1, (sy) # Preload y slope with 1
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movw $1, (sy) # Preload the y slope with 1
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cmpw y1, %dx # Check if y1 is less than y0 and we can start our plotting
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cmpw y1, %dx # Check if y0 is less than y1 and we can start our plotting
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jl cons_line_prep_loop
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jl cons_line_prep_loop
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negw sy # if y1 is greater than we need to flip the slope y and delta y values
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negw sy # if y1 is greater than we need to flip the slope y and delta y values
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negw deltay
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negw deltay
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@ -136,7 +137,7 @@ cons_line_loop_start:
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jmp cons_line_loop_end # if both x's and y's are equal then we can end the function
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jmp cons_line_loop_end # if both x's and y's are equal then we can end the function
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cons_line_loop_next_point:
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cons_line_loop_next_point:
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movw err, %ax # Load err into ax so that we can multiply it
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movw err, %ax # Load err into ax so that we can change it
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add %ax, %ax # e2 is 2 * err, so we can just add err to itself
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add %ax, %ax # e2 is 2 * err, so we can just add err to itself
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cons_line_loop_move_y_point:
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cons_line_loop_move_y_point:
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@ -170,75 +171,75 @@ draw_start:
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int $0x10
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int $0x10
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xor %ax, %ax
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xor %ax, %ax
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movw $50, %ax # Plot a line, ax = x0, bx = x1, cl = y0, ch = y1, dl = color
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movw $50, %ax # Plot a line, ax = x0, bx = y0, cx = x1, dx = y1, si = color
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movb $50, %cl # the X values require a full register but the y's only require a byte since the max value is 200
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movw $50, %bx
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movw $160, %bx
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movw $160, %cx
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movb $55, %ch
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movw $55, %dx
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movb $12, %dl # The Color also only requires a byte
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movw $12, %si # The Color using the si counter because we dont have enough normal registers
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call cons_draw_line
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call cons_draw_line
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# Draw the rest of the lines
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# Draw the rest of the lines
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movw $160, %ax
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movw $160, %ax
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movb $55, %cl
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movw $55, %bx
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movw $90, %bx
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movw $90, %cx
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movb $150, %ch
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movw $150, %dx
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movb $11, %dl
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movw $11, %si
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call cons_draw_line
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call cons_draw_line
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movw $90, %ax
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movw $90, %ax
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movb $150, %cl
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movw $150, %bx
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movw $50, %bx
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movw $50, %cx
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movb $50, %ch
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movw $50, %dx
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movb $14, %dl
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movw $14, %si
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call cons_draw_line
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call cons_draw_line
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movw $10, %ax
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movw $10, %ax
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movb $10, %cl
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movw $310, %bx
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movb $10, %ch
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movb $9, %dl
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call cons_draw_line
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movw $310, %ax
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movb $10, %cl
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movw $310, %bx
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movb $190, %ch
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movb $10, %dl
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call cons_draw_line
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movw $310, %ax
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movb $190, %cl
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movw $10, %bx
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movw $10, %bx
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movb $190, %ch
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movw $310, %cx
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movb $13, %dl
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movw $10, %dx
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movw $9, %si
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call cons_draw_line
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movw $310, %ax
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movw $10, %bx
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movw $310, %cx
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movw $190, %dx
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movw $10, %si
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call cons_draw_line
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movw $310, %ax
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movw $190, %bx
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movw $10, %cx
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movw $190, %dx
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movw $13, %si
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call cons_draw_line
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call cons_draw_line
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movw $10, %ax
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movw $10, %ax
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movb $190, %cl
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movw $190, %bx
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movw $10, %bx
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movw $10, %cx
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movb $10, %ch
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movw $10, %dx
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movb $15, %dl
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movw $15, %si
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call cons_draw_line
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call cons_draw_line
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movw $75, %ax
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movw $75, %ax
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movb $150, %cl
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movw $150, %bx
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movw $250, %bx
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movw $250, %cx
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movb $110, %ch
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movw $110, %dx
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movb $1, %dl
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movw $1, %si
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call cons_draw_line
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call cons_draw_line
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movw $210, %ax
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movw $210, %ax
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movb $30, %cl
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movw $30, %bx
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movw $300, %bx
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movw $300, %cx
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movb $150, %ch
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movw $150, %dx
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movb $6, %dl
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movw $6, %si
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call cons_draw_line
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call cons_draw_line
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movw $180, %ax
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movw $180, %ax
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movb $180, %cl
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movw $180, %bx
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movw $170, %bx
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movw $170, %cx
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movb $20, %ch
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movw $20, %dx
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movb $3, %dl
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movw $3, %si
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call cons_draw_line
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call cons_draw_line
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endless_loop: # Loop forever more
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endless_loop: # Loop forever more
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@ -258,4 +259,4 @@ sx: .word 0
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sy: .word 0
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sy: .word 0
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err: .word 0
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err: .word 0
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e2: .word 0
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e2: .word 0
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color: .byte 0
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color: .word 0
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Binary file not shown.
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BIN
stage1/xv6.img
BIN
stage1/xv6.img
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13
stage2/.vscode/tasks.json
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13
stage2/.vscode/tasks.json
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@ -0,0 +1,13 @@
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{
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// See https://go.microsoft.com/fwlink/?LinkId=733558
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// for the documentation about the tasks.json format
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"version": "2.0.0",
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"tasks": [
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{
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"label": "Build and QEMU",
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"type": "shell",
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"command": "make qemu",
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"problemMatcher": []
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}
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]
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}
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102
stage2/Makefile
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102
stage2/Makefile
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@ -0,0 +1,102 @@
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# Try to infer the correct TOOLPREFIX if not set
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ifndef TOOLPREFIX
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TOOLPREFIX := $(shell if i386-jos-elf-objdump -i 2>&1 | grep '^elf32-i386$$' >/dev/null 2>&1; \
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then echo 'i386-jos-elf-'; \
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elif objdump -i 2>&1 | grep 'elf32-i386' >/dev/null 2>&1; \
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then echo ''; \
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else echo "***" 1>&2; \
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echo "*** Error: Couldn't find an i386-*-elf version of GCC/binutils." 1>&2; \
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echo "*** Is the directory with i386-jos-elf-gcc in your PATH?" 1>&2; \
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echo "*** If your i386-*-elf toolchain is installed with a command" 1>&2; \
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echo "*** prefix other than 'i386-jos-elf-', set your TOOLPREFIX" 1>&2; \
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|
echo "*** environment variable to that prefix and run 'make' again." 1>&2; \
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echo "*** To turn off this error, run 'gmake TOOLPREFIX= ...'." 1>&2; \
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echo "***" 1>&2; exit 1; fi)
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|
endif
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# If the makefile can't find QEMU, specify its path here
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|
# QEMU = qemu-system-i386
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|
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|
# Try to infer the correct QEMU
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|
ifndef QEMU
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|
QEMU = $(shell if which qemu > /dev/null; \
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|
then echo qemu; exit; \
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|
elif which qemu-system-i386 > /dev/null; \
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|
then echo qemu-system-i386; exit; \
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|
elif which qemu-system-x86_64 > /dev/null; \
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|
then echo qemu-system-x86_64; exit; \
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|
else \
|
||||||
|
qemu=/Applications/Q.app/Contents/MacOS/i386-softmmu.app/Contents/MacOS/i386-softmmu; \
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|
if test -x $$qemu; then echo $$qemu; exit; fi; fi; \
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|
echo "***" 1>&2; \
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|
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; \
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|
echo "***" 1>&2; exit 1)
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|
endif
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|
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|
CC = $(TOOLPREFIX)gcc
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|
AS = $(TOOLPREFIX)gas
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|
LD = $(TOOLPREFIX)ld
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|
OBJCOPY = $(TOOLPREFIX)objcopy
|
||||||
|
OBJDUMP = $(TOOLPREFIX)objdump
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|
CFLAGS = -fno-pic -static -fno-builtin -fno-strict-aliasing -O2 -Wall -MD -ggdb -m32 -Werror -fno-omit-frame-pointer
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|
CFLAGS += $(shell $(CC) -fno-stack-protector -E -x c /dev/null >/dev/null 2>&1 && echo -fno-stack-protector)
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|
ASFLAGS = -m32 -gdwarf-2 -Wa,-divide
|
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|
# 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
|
||||||
|
|
||||||
101
stage2/bootasm.S
Normal file
101
stage2/bootasm.S
Normal file
@ -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.
|
||||||
|
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||||||
|
.code16 # Assemble for 16-bit mode
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||||||
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.globl start
|
||||||
|
start:
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||||||
|
jmp real_start
|
||||||
|
|
||||||
|
# Write to the console using BIOS.
|
||||||
|
#
|
||||||
|
# Input: SI contains the address of the null-terminated string to be displayed
|
||||||
|
|
||||||
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cons_write:
|
||||||
|
movb $0x0e, %ah # 0x0e is the INT 10h BIOS call to output the value contained in AL to screen
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||||||
|
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||||||
|
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
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||||||
|
jz cons_write_done # If it is zero, then we are done
|
||||||
|
int $0x10 # Output the character in AL to the screen
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||||||
|
jmp cons_write_rpt # and continue
|
||||||
|
|
||||||
|
cons_write_done: # Something that is called will never return
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||||||
|
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"
|
||||||
|
|
||||||
1
stage2/bootasm.d
Normal file
1
stage2/bootasm.d
Normal file
@ -0,0 +1 @@
|
|||||||
|
bootasm.o: bootasm.S
|
||||||
BIN
stage2/bootasm.o
Normal file
BIN
stage2/bootasm.o
Normal file
Binary file not shown.
283
stage2/bootasm2.S
Normal file
283
stage2/bootasm2.S
Normal file
@ -0,0 +1,283 @@
|
|||||||
|
# Second stage of the boot loader
|
||||||
|
|
||||||
|
.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
|
||||||
|
|
||||||
|
# Added Write Hex and Int functions to help with debugging
|
||||||
|
HexChars: .ascii "0123456789ABCDEF"
|
||||||
|
|
||||||
|
cons_write_hex:
|
||||||
|
movw $4, %cx
|
||||||
|
movb $0x0E, %ah
|
||||||
|
|
||||||
|
hexloop:
|
||||||
|
rol $4, %bx
|
||||||
|
movw %bx, %si
|
||||||
|
and $0x000F, %si
|
||||||
|
movb HexChars(%si), %al
|
||||||
|
int $0x10
|
||||||
|
loop hexloop
|
||||||
|
ret
|
||||||
|
|
||||||
|
cons_write_int:
|
||||||
|
movw $IntBuffer + 4, %si
|
||||||
|
movw %bx, %ax
|
||||||
|
|
||||||
|
cmpw $0, %ax
|
||||||
|
jge getdigit
|
||||||
|
|
||||||
|
xor %ax, %ax # Added to handle signed numbers, it adds the minus and then neg's the number
|
||||||
|
movb $0x0E, %ah
|
||||||
|
movb $0x2D, %al
|
||||||
|
int $0x10
|
||||||
|
|
||||||
|
movw %bx, %ax
|
||||||
|
negw %ax
|
||||||
|
|
||||||
|
getdigit:
|
||||||
|
xor %dx, %dx
|
||||||
|
movw $10, %cx
|
||||||
|
idiv %cx
|
||||||
|
addb $48, %dl
|
||||||
|
movb %dl, (%si)
|
||||||
|
dec %si
|
||||||
|
cmp $0, %ax
|
||||||
|
jne getdigit
|
||||||
|
inc %si
|
||||||
|
call cons_write
|
||||||
|
ret
|
||||||
|
|
||||||
|
IntBuffer: .string " "
|
||||||
|
|
||||||
|
# Draw Line function DrawLine(x0 (4), y0 (6), x1 (8), y1 (10), color (12))
|
||||||
|
# Define parameter address positions in stack
|
||||||
|
#define color 12
|
||||||
|
#define y1 10
|
||||||
|
#define x1 8
|
||||||
|
#define y0 6
|
||||||
|
#define x0 4
|
||||||
|
|
||||||
|
# Define local variable positions in stack
|
||||||
|
#define deltax -2
|
||||||
|
#define deltay -4
|
||||||
|
#define sx -6
|
||||||
|
#define sy -8
|
||||||
|
#define err -10
|
||||||
|
#define e2 -12
|
||||||
|
|
||||||
|
cons_draw_line:
|
||||||
|
pushw %bp
|
||||||
|
movw %sp, %bp
|
||||||
|
subw $12, %sp # Make room for our local variables in the stack
|
||||||
|
|
||||||
|
# Store existing register values to the stack so we can restore later
|
||||||
|
pushw %ax
|
||||||
|
pushw %bx
|
||||||
|
pushw %cx
|
||||||
|
pushw %dx
|
||||||
|
pushw %si
|
||||||
|
pushw %di
|
||||||
|
|
||||||
|
movw $0, err(%bp) # Make sure that err starts at 0
|
||||||
|
movw x1(%bp), %cx # Load x1 and y1 into the registers
|
||||||
|
movw y1(%bp), %dx
|
||||||
|
sub x0(%bp), %cx # Remove x/y0 from x/y1 to get the delta values
|
||||||
|
sub y0(%bp), %dx
|
||||||
|
movw %cx, deltax(%bp) # Store the delta values
|
||||||
|
movw %dx, deltay(%bp)
|
||||||
|
|
||||||
|
cons_line_check_x:
|
||||||
|
movw x0(%bp), %cx # Load x0 into register cx so we can manipulate this value to plot each pixel
|
||||||
|
movw $1, sx(%bp) # Preload the x slope with 1
|
||||||
|
cmp x1(%bp), %cx # Check if x0 is less than x1 and we can move to y
|
||||||
|
jl cons_line_check_y
|
||||||
|
negw sx(%bp) # If x1 is greater than we need to flip the slope and the x delta values
|
||||||
|
negw deltax(%bp) # Flipping the deltax here saves us from having to have an abs function because if
|
||||||
|
# x0 was greater than x1 we know we have a negative delta value and we flip it to pos
|
||||||
|
|
||||||
|
cons_line_check_y:
|
||||||
|
movw y0(%bp), %dx # Load y0 into register dx so we can manipulate this value to plot each pixel
|
||||||
|
movw $1, sy(%bp) # Preload the y slope with 1
|
||||||
|
cmpw y1(%bp), %dx # Check if y0 is less than y1 and we can start our plotting
|
||||||
|
jl cons_line_prep_loop
|
||||||
|
negw sy(%bp) # if y1 is greater than we need to flip the slope y and delta y values
|
||||||
|
negw deltay(%bp)
|
||||||
|
|
||||||
|
cons_line_prep_loop:
|
||||||
|
movw deltax(%bp), %ax # Calculate the err variable by subtracting delta y from delta x
|
||||||
|
sub deltay(%bp), %ax
|
||||||
|
movw %ax, err(%bp)
|
||||||
|
|
||||||
|
cons_line_loop_start:
|
||||||
|
xor %ax, %ax # Clear ax and bx for use with the draw function
|
||||||
|
xor %bx, %bx
|
||||||
|
movb $0x0c, %ah # Set the function byte to plot the pixel
|
||||||
|
movb $0, %bh # Set the video page number
|
||||||
|
movb color(%bp), %al # Set the color of the pixel
|
||||||
|
int $0x10 # Call the int
|
||||||
|
|
||||||
|
cmpw x1(%bp), %cx # Check if x0 and x1 are equal, if not then we are still plotting
|
||||||
|
jne cons_line_loop_next_point
|
||||||
|
cmpw y1(%bp), %dx # Check if y0 and y1 are equal, if not then we are still plotting
|
||||||
|
jne cons_line_loop_next_point
|
||||||
|
jmp cons_line_loop_end # if both x's and y's are equal then we can end the function
|
||||||
|
|
||||||
|
cons_line_loop_next_point:
|
||||||
|
movw err(%bp), %ax # Load err into ax so that we can change it
|
||||||
|
add %ax, %ax # e2 is 2 * err, so we can just add err to itself
|
||||||
|
|
||||||
|
cons_line_loop_move_y_point:
|
||||||
|
movw deltay(%bp), %bx
|
||||||
|
negw %bx # We need negative deltay to compare
|
||||||
|
cmpw %bx, %ax # Check if we need to apply the slope value to y
|
||||||
|
jle cons_line_loop_move_x_point
|
||||||
|
negw %bx # Change deltay back to normal
|
||||||
|
subw %bx, err(%bp) # Remove the deltay from the err check
|
||||||
|
addw sx(%bp), %cx # Add the slope value to the current y value
|
||||||
|
|
||||||
|
cons_line_loop_move_x_point:
|
||||||
|
movw deltax(%bp), %bx
|
||||||
|
cmpw %bx, %ax # Check if we need to apply the x slope value
|
||||||
|
jge cons_line_loop_start
|
||||||
|
addw %bx, err(%bp) # Add the deltax to the err value
|
||||||
|
addw sy(%bp), %dx # Add the slope value to the current x value
|
||||||
|
jmp cons_line_loop_start # Go back to the start of the loop
|
||||||
|
|
||||||
|
cons_line_loop_end:
|
||||||
|
# Return all the original values to each register before we return back
|
||||||
|
popw %di
|
||||||
|
popw %si
|
||||||
|
popw %dx
|
||||||
|
popw %cx
|
||||||
|
popw %bx
|
||||||
|
popw %ax
|
||||||
|
movw %bp, %sp
|
||||||
|
popw %bp
|
||||||
|
ret $10 # Finish the loop and return to the call address
|
||||||
|
# we also tell it to free the 10 bytes in the stack for the paramters
|
||||||
|
# 5 x Word (2 bytes)
|
||||||
|
|
||||||
|
real_start:
|
||||||
|
movw $boot_message, %si # Display our boot message
|
||||||
|
call cons_writeline
|
||||||
|
|
||||||
|
draw_start:
|
||||||
|
# Set the Video mode to VGA 320 x 200 x 8
|
||||||
|
movb $0, %ah
|
||||||
|
movb $0x13, %al
|
||||||
|
int $0x10
|
||||||
|
xor %ax, %ax
|
||||||
|
|
||||||
|
# Plot a line, we add the parameters to the stack in reverse order
|
||||||
|
pushw $12 # Color
|
||||||
|
pushw $55 # y1
|
||||||
|
pushw $160 # x1
|
||||||
|
pushw $50 # y0
|
||||||
|
pushw $50 # x0
|
||||||
|
call cons_draw_line
|
||||||
|
|
||||||
|
# Draw the rest of the lines
|
||||||
|
pushw $11 # Color
|
||||||
|
pushw $150 # y1
|
||||||
|
pushw $90 # x1
|
||||||
|
pushw $55 # y0
|
||||||
|
pushw $160 # x0
|
||||||
|
call cons_draw_line
|
||||||
|
|
||||||
|
pushw $14 # Color
|
||||||
|
pushw $50 # y1
|
||||||
|
pushw $50 # x1
|
||||||
|
pushw $150 # y0
|
||||||
|
pushw $90 # x0
|
||||||
|
call cons_draw_line
|
||||||
|
|
||||||
|
pushw $9 # Color
|
||||||
|
pushw $10 # y1
|
||||||
|
pushw $310 # x1
|
||||||
|
pushw $10 # y0
|
||||||
|
pushw $10 # x0
|
||||||
|
call cons_draw_line
|
||||||
|
|
||||||
|
pushw $10 # Color
|
||||||
|
pushw $190 # y1
|
||||||
|
pushw $310 # x1
|
||||||
|
pushw $10 # y0
|
||||||
|
pushw $310 # x0
|
||||||
|
call cons_draw_line
|
||||||
|
|
||||||
|
pushw $13 # Color
|
||||||
|
pushw $190 # y1
|
||||||
|
pushw $10 # x1
|
||||||
|
pushw $190 # y0
|
||||||
|
pushw $310 # x0
|
||||||
|
call cons_draw_line
|
||||||
|
|
||||||
|
pushw $15 # Color
|
||||||
|
pushw $10 # y1
|
||||||
|
pushw $10 # x1
|
||||||
|
pushw $190 # y0
|
||||||
|
pushw $10 # x0
|
||||||
|
call cons_draw_line
|
||||||
|
|
||||||
|
pushw $1 # Color
|
||||||
|
pushw $110 # y1
|
||||||
|
pushw $250 # x1
|
||||||
|
pushw $150 # y0
|
||||||
|
pushw $75 # x0
|
||||||
|
call cons_draw_line
|
||||||
|
|
||||||
|
pushw $6 # Color
|
||||||
|
pushw $150 # y1
|
||||||
|
pushw $300 # x1
|
||||||
|
pushw $30 # y0
|
||||||
|
pushw $210 # x0
|
||||||
|
call cons_draw_line
|
||||||
|
|
||||||
|
pushw $3 # Color
|
||||||
|
pushw $20 # y1
|
||||||
|
pushw $170 # x1
|
||||||
|
pushw $180 # y0
|
||||||
|
pushw $180 # x0
|
||||||
|
call cons_draw_line
|
||||||
|
|
||||||
|
endless_loop: # Loop forever more
|
||||||
|
jmp endless_loop
|
||||||
|
|
||||||
|
# Program data
|
||||||
|
boot_message:
|
||||||
|
.string "Boot Loader Stage 2 loaded"
|
||||||
1
stage2/bootasm2.d
Normal file
1
stage2/bootasm2.d
Normal file
@ -0,0 +1 @@
|
|||||||
|
bootasm2.o: bootasm2.S
|
||||||
BIN
stage2/bootblock
Normal file
BIN
stage2/bootblock
Normal file
Binary file not shown.
BIN
stage2/bootblock.o
Normal file
BIN
stage2/bootblock.o
Normal file
Binary file not shown.
BIN
stage2/bootblock2
Normal file
BIN
stage2/bootblock2
Normal file
Binary file not shown.
BIN
stage2/bootblock2.o
Normal file
BIN
stage2/bootblock2.o
Normal file
Binary file not shown.
19
stage2/sign.pl
Normal file
19
stage2/sign.pl
Normal file
@ -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;
|
||||||
BIN
stage2/xv6.img
(Stored with Git LFS)
Normal file
BIN
stage2/xv6.img
(Stored with Git LFS)
Normal file
Binary file not shown.
Reference in New Issue
Block a user