add most of the xterm palette

boot.s

@@ -2,14 +2,65 @@
 
 .global _start # the linker needs to find it
 _start:
-	jmp _real_start
+	jmp vga_init
 	.ascii "I'm bootable!"
 
-_real_start:
+_Xterm_grad:
+	.byte 0x00, 0x5f / 4, 0x87 / 4, 0xaf / 4, 0xd7 / 4, 0xff / 4
+
+vga_init:
 	# enter mode 13h
 	mov $0x13, %ax
 	int $0x10
 
+	# prepare the xterm palette 16-231
+	# bh - color id
+	# dx - used up for the port number
+	mov $16, %bh
+	xor %ecx, %ecx # dumb as bullshit
+palette_loop:
+	mov %bh, %al
+	mov $0x3c8, %dx
+	out %al, %dx
+	inc %dx
+
+	sub $16, %al # the colors start at 16, real_id = id - 16
+	mov $6, %bl
+
+	xor %ah, %ah
+	div %bl      # al = real_id / 6
+	             # ah = remainder
+	mov %ah, %cl # cl = real_id % 6
+
+	xor %ah, %ah
+	div %bl      # al = real_id / 6 / 6
+	             # ah = remainder
+	
+	# at this point
+	#   al - R
+	#   ah - G
+	#   cl - B (soon bl)
+
+	# because of some dumb as bullshit, i need to use ecx for stuff
+	mov %cl, %bl
+
+	mov %al, %cl
+	mov _Xterm_grad(%ecx), %al
+	out %al, %dx
+
+	mov %ah, %cl
+	mov _Xterm_grad(%ecx), %al
+	out %al, %dx
+
+	mov %bl, %cl
+	mov _Xterm_grad(%ecx), %al
+	out %al, %dx
+
+	inc %bh
+	jnz palette_loop # loop until 0
+	# TODO first 16 + grayscale
+
+before_loop:
 	mov $0xA000, %ax # ES = vga memory
 	mov %ax, %es
 
@@ -37,7 +88,10 @@ not_eol:
 	jl loop
 
 	incb %es:319
+end:
 	hlt
+	jmp end
 
+# .fill (510-(.-_start))/4, 4, 0xc4c5c6c7 # color stripes for testing
 .fill 510-(.-_start), 1, 0x90 # fill with 0x90 (NOPs)
 .word 0xaa55                  # boot sector magic