diff options
Diffstat (limited to 'asm-notes.txt')
| -rw-r--r-- | asm-notes.txt | 77 |
1 files changed, 77 insertions, 0 deletions
diff --git a/asm-notes.txt b/asm-notes.txt new file mode 100644 index 0000000..03bf335 --- /dev/null +++ b/asm-notes.txt @@ -0,0 +1,77 @@ + + + + ; opcode c7 is Ev, Iz. c6 is Eb, Ib + ; Eb: ModR/M to follow, byte + ; consider 1100 011w : 11 000 reg : imm + ; also consider 1011 w reg : imm for bytes + +32-bit target, 8-bit source + match =eax?, target + db 0xB8 + dd source + else match =edi?, target + db 0xBF + dd source + +64-bit target, 32-bit source + match =rax?, target ; mov rax, 0x1234 + db 0x48, 0xC7, 0xC0 + dd source +; 48 eAX REX.W prefix +; (DEC is the 32-bit meaning, ignore it) +; eAX -> register identifier, +; width depends on operand +; REX.W -> set 64-bit operand mode +; c7 Grp 11^1A - MOV Ev, Iz +; immediate to register +; 1A -> bits 5,4,3 of ModR/M are opcode +; extension +; E -> modR/M byte to follow for operand +; v -> word of appropriate size +; I -> immediate data +; z -> 32-bit operand +; c0 ModR/M byte +; 0b11000000 +; 11 mod: always 11 +; 000 op/reg: Mov Ev, Iz +; 00x w absent +; 0 w (ignored) + + + + match =rdi, target ; mov rdi, 0x1234 + db 0x48, 0xC7, 0xC7 + dd source +; 7: 48 c7 c7 2a 00 00 00 mov $0x2a,%rdi +; 48 eAX REX.W prefix +; (DEC is the 32-bit meaning, ignore it) +; c7 Grp 11^1A - MOV Ev, Iz +; immediate to register +; 1A -> bits 5,4,3 of ModR/M are opcode +; extension +; Ev -> ModR/M to follow for 32-bit operand +; Iz -> Immediate data, 32-bits +; c7 ModR/M byte +; 0b11000111 +; 11 mod: always 11 +; 000 op/reg: Mov Ev, Iz +; 11x w present +; 1 w true; use EDI + + + +64-bit target, 64-bi source + + match =rdi, target ; mov rdi, 0x1234 + db 0x48, 0xB8, 0x38 + dq source + + match =rsi, target + db 0x48, 0xB8, 0x30 + dq source + ; opcode c7 is Ev, Iz. c6 is Eb, Ib + ; Eb: ModR/M to follow, byte + ; consider 1100 011w : 11 000 reg : imm + ; also consider 1011 w reg : imm for bytes + |