From 6e1eeeebfb453fa7c871869c19375ce60fbd7413 Mon Sep 17 00:00:00 2001 From: Kartik Agaram Date: Sat, 27 Jul 2019 16:01:55 -0700 Subject: 5485 - promote SubX to top-level --- html/examples/ex9.subx.html | 117 ++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 117 insertions(+) create mode 100644 html/examples/ex9.subx.html (limited to 'html/examples/ex9.subx.html') diff --git a/html/examples/ex9.subx.html b/html/examples/ex9.subx.html new file mode 100644 index 00000000..61491047 --- /dev/null +++ b/html/examples/ex9.subx.html @@ -0,0 +1,117 @@ + + + + +Mu - subx/examples/ex9.subx + + + + + + + + + + +https://github.com/akkartik/mu/blob/master/subx/examples/ex9.subx +
+ 1 # Example showing arg order on the stack.
+ 2 #
+ 3 # Show difference between ascii codes of first letter of first arg and first
+ 4 # letter of second arg.
+ 5 #
+ 6 # To run (from the subx directory):
+ 7 #   $ ./subx translate examples/ex9.subx -o examples/ex9
+ 8 #   $ ./subx run examples/ex9 z x
+ 9 # Expected result:
+10 #   $ echo $?
+11 #   2
+12 #
+13 # At the start of a SubX program:
+14 #   argc: *ESP
+15 #   argv[0]: *(ESP+4)
+16 #   argv[1]: *(ESP+8)
+17 #   ...
+18 # Locals start from ESP-4 downwards.
+19 
+20 == code 0x09000000
+21 #   instruction                     effective address                                                   register    displacement    immediate
+22 # . op          subop               mod             rm32          base        index         scale       r32
+23 # . 1-3 bytes   3 bits              2 bits          3 bits        3 bits      3 bits        2 bits      2 bits      0/1/2/4 bytes   0/1/2/4 bytes
+24 
+25 Entry:
+26     # . prolog
+27     89/copy                         3/mod/direct    5/rm32/EBP    .           .             .           4/r32/ESP   .               .                 # copy ESP to EBP
+28     # ascii-difference(argv[1], argv[2])
+29     # . . push argv[2]
+30     ff          6/subop/push        1/mod/*+disp8   5/rm32/EBP    .           .             .           .           0xc/disp8       .                 # push *(EBP+12)
+31     # . . push argv[1]
+32     ff          6/subop/push        1/mod/*+disp8   5/rm32/EBP    .           .             .           .           8/disp8         .                 # push *(EBP+8)
+33     # . . call
+34     e8/call  ascii-difference/disp32
+35     # . . discard args
+36     81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               8/imm32           # add to ESP
+37     # syscall(exit, EAX)
+38     89/copy                         3/mod/direct    3/rm32/EBX    .           .             .           0/r32/EAX   .               .                 # copy EAX to EBX
+39     b8/copy-to-EAX  1/imm32/exit
+40     cd/syscall  0x80/imm8
+41 
+42 ascii-difference:  # (s1, s2) : null-terminated ascii strings
+43     # a = first letter of s1 (ECX)
+44     8b/copy                         1/mod/*+disp8   4/rm32/sib    4/base/ESP  4/index/none              0/r32/EAX   4/disp8         .                 # copy *(ESP+4) to EAX
+45     8b/copy                         0/mod/indirect  0/rm32/EAX    .           .             .           0/r32/EAX   .               .                 # copy *EAX to EAX
+46     # b = first letter of s2 (EDX)
+47     8b/copy                         1/mod/*+disp8   4/rm32/sib    4/base/ESP  4/index/none              1/r32/ECX   8/disp8                           # copy *(ESP+8) to ECX
+48     8b/copy                         0/mod/indirect  1/rm32/ECX    .           .             .           1/r32/ECX   .               .                 # copy *ECX to ECX
+49     # a-b
+50     29/subtract                     3/mod/direct    0/rm32/EAX    .           .             .           1/r32/ECX   .               .                 # subtract ECX from EAX
+51     c3/return
+52 
+53 == data 0x0a000000
+54 
+55 # . . vim:nowrap:textwidth=0
+
+ + + -- cgit 1.4.1-2-gfad0