From 3350c34a74844e21ea69077e01efff3bae64bdcd Mon Sep 17 00:00:00 2001 From: Kartik Agaram Date: Tue, 23 Mar 2021 17:31:08 -0700 Subject: . --- html/linux/303kernel-string.subx.html | 151 ++++++++++++++++++++++++++++++++++ 1 file changed, 151 insertions(+) create mode 100644 html/linux/303kernel-string.subx.html (limited to 'html/linux/303kernel-string.subx.html') diff --git a/html/linux/303kernel-string.subx.html b/html/linux/303kernel-string.subx.html new file mode 100644 index 00000000..84f13d5c --- /dev/null +++ b/html/linux/303kernel-string.subx.html @@ -0,0 +1,151 @@ + + + + +Mu - linux/303kernel-string.subx + + + + + + + + + + +https://github.com/akkartik/mu/blob/main/linux/303kernel-string.subx +
+ 1 # We can't really do much with null-terminated kernel strings, and we don't
+ 2 # want to. Let's turn them into regular length-prefixed strings at the first
+ 3 # opportunity.
+ 4 
+ 5 == code
+ 6 
+ 7 kernel-string-to-string:  # ad: (addr allocation-descriptor), in: (addr kernel-string), out: (addr handle array byte)
+ 8     # . prologue
+ 9     55/push-ebp
+10     89/<- %ebp 4/r32/esp
+11     # . save registers
+12     51/push-ecx
+13     52/push-edx
+14     53/push-ebx
+15     56/push-esi
+16     57/push-edi
+17     # var len/ecx: int = length(in)
+18     (kernel-string-length *(ebp+0xc))
+19     89/<- %ecx 0/r32/eax
+20     # result = allocate-array(ad, len)
+21     (allocate-array *(ebp+8) %ecx *(ebp+0x10))
+22     # var c/edx: byte = 0
+23     ba/copy-to-edx 0/imm32
+24     # var src/esi: (addr byte) = in
+25     8b/-> *(ebp+0xc) 6/r32/esi
+26     # var dest/edi: (addr byte) = result->data
+27     8b/-> *(ebp+0x10) 7/r32/edi
+28     (lookup *edi *(edi+4))  # => eax
+29     8d/copy-address *(eax+4) 7/r32/edi
+30     {
+31 $kernel-string-to-string:loop:
+32       # c = *src
+33       8a/byte-> *esi 2/r32/dl
+34       # if (c == 0) break
+35       81 7/subop/compare %edx 0/imm32
+36       74/jump-if-= break/disp8
+37       # *dest = c
+38       88/byte<- *edi 2/r32/dl
+39       # ++src
+40       46/increment-esi
+41       # ++dest
+42       47/increment-edi
+43       eb/jump loop/disp8
+44     }
+45 $kernel-string-to-string:end:
+46     # . restore registers
+47     5f/pop-to-edi
+48     5e/pop-to-esi
+49     5b/pop-to-ebx
+50     5a/pop-to-edx
+51     59/pop-to-ecx
+52     # . epilogue
+53     89/<- %esp 5/r32/ebp
+54     5d/pop-to-ebp
+55     c3/return
+56 
+57 kernel-string-length:  # in: (addr kernel-string) -> result/eax: int
+58     # . prologue
+59     55/push-ebp
+60     89/<- %ebp 4/r32/esp
+61     # . save registers
+62     51/push-ecx
+63     52/push-edx
+64     # result = 0
+65     b8/copy-to-eax 0/imm32
+66     # var c/ecx: byte = 0
+67     b9/copy-to-ecx 0/imm32
+68     # var curr/edx: (addr byte) = in
+69     8b/-> *(ebp+8) 2/r32/edx
+70     {
+71 $kernel-string-length:loop:
+72       # c = *curr
+73       8a/byte-> *edx 1/r32/ecx
+74       # if (c == 0) break
+75       81 7/subop/compare %ecx 0/imm32
+76       74/jump-if-= break/disp8
+77       # ++curr
+78       42/increment-edx
+79       # ++result
+80       40/increment-eax
+81       #
+82       eb/jump loop/disp8
+83     }
+84 $kernel-string-length:end:
+85     # . restore registers
+86     5a/pop-to-edx
+87     59/pop-to-ecx
+88     # . epilogue
+89     89/<- %esp 5/r32/ebp
+90     5d/pop-to-ebp
+91     c3/return
+
+ + + -- cgit 1.4.1-2-gfad0