Print number of sectors

src/x86_stage1.S

@@ -37,6 +37,7 @@ newline: .string "\r\n"
 hello: .string "Hello from stage 1!\r\n"
 stage1_size_str: .string "Stage 1 size: "
 stage2_size_str: .string "Stage 2 size: "
+number_of_sectors: .string "Number of sectors: "
 
 main:
     cli
@@ -70,6 +71,26 @@ main:
     mov (%bx), %ax
     call print_size
 
+    // DX - dividend high (always zero)
+    xor %dx, %dx
+    // AX - dividend low
+    mov $STAGE2_ADDR(size), %bx
+    mov (%bx), %ax
+    // BX - divisor (always 512)
+    mov $512, %bx
+    // AX - quotient
+    // DX - remainder
+    div %bx
+
+    test %dx, %dx
+    jz no_rem
+    inc %ax
+no_rem:
+    // AX - number of sectors
+    push %ax
+    call print_number_of_sectors
+    pop %ax
+
     ljmp $0, $STAGE2_BASE
 
 hang:
@@ -144,4 +165,19 @@ print_size:
 
     ret
 
+// AX - number of sectors
+print_number_of_sectors:
+    push %ax
+
+    mov $STAGE1_ADDR(number_of_sectors), %si
+    call print_str
+
+    pop %ax
+    call print_number
+
+    mov $STAGE1_ADDR(newline), %si
+    call print_str
+
+    ret
+
 _end:

src/x86_stage2.S

@@ -61,4 +61,6 @@ print_str:
     call print_char
     jmp print_str
 
+.fill 512, 1, 0
+
 _end: