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@@ -15,6 +15,8 @@
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;; You should have received a copy of the GNU General Public License
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;; along with this program. If not, see <https://www.gnu.org/licenses/>.
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+ PROGRAM_SIZE equ 0x100000
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+ SKIP_SIZE equ 0x1000000
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start_from_raw:
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start_from_multiboot:
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@@ -22,36 +24,16 @@ start_from_multiboot:
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;; Store the address of the script in ESI
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mov esi, initrd
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- ;; Delete comments and find the final "s"
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- mov ecx, esi
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-find_s:
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- cmp BYTE [ecx], 0x23
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- je remove_comment
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- cmp BYTE [ecx], 0x73
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- je found_s
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- add ecx, 1
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- jmp find_s
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-
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-remove_comment:
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- mov BYTE [ecx], 0x20
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- add ecx, 1
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- cmp BYTE [ecx], 0x0a
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- jne remove_comment
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- jmp find_s
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-
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- ;; Store the position after the final "s" in EDI
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-found_s:
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- add ecx, 1
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- mov edi, ecx
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-
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- ;; Allocate 64kB for the stack and align to 4 bytes
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- add edi, 0x10000
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- and edi, 0xfffffff0
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+ ;; Skip some space in order not to touch other data; align to
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+ ;; 4 and set the stack pointer
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+ mov edi, esi
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+ add edi, SKIP_SIZE
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+ and edi, 0xffffff0
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mov esp, edi
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- ;; Fill 1MB of space with 0x90 (NOPs)
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+ ;; Fill the program with 0x90 (NOPs)
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mov edx, edi
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- mov ecx, 0x100000
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+ mov ecx, PROGRAM_SIZE
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nops_fill:
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cmp ecx, 0
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je nops_filled
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@@ -59,8 +41,8 @@ nops_fill:
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mov BYTE [edx], 0x90
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add edx, 1
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jmp nops_fill
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-nops_filled:
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+nops_filled:
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;; Initialize the accumulator (EAX) to 0
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mov eax, 0
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@@ -80,6 +62,9 @@ compile_char:
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cmp bl, 0x20
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je compile_loop
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+ cmp bl, 0x23
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+ je skip_comment
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+
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cmp bl, 0x43
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je code_C
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cmp bl, 0x47
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@@ -121,6 +106,13 @@ compile_loop:
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jmp compile_char
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+skip_comment:
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+ cmp BYTE [esi], 0xa
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+ je compile_loop
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+ add esi, 1
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+ jmp skip_comment
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+
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+
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;; Process a digit into the accumulator
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code_hex_digit:
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add bl, 10
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@@ -147,9 +139,12 @@ code_S:
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code_s:
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;; Check that we did not overflow the allocated 1MB
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mov edx, ecx
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- add edx, 0x100000
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+ add edx, PROGRAM_SIZE
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cmp edi, edx
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ja failure
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+ ;; Push the source end
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+ add esi, 1
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+ push esi
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;; Call the compiled code
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call ecx
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;; call dump_code_and_die
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Giovanni Mascellani