;; ;; dumpregs.asm ;; ;; Programmer : Terry Sergeant ;; Version : 11 Oct 2022 ;; Description: macros useful for showing contents of registers ... can ;; be helpful in debugging, etc. ;; ;; 11 Oct 2022 NOTES - For systems that require gcc -no-pie switch we must ;; make sure that the stack is aligned which means that we need an even ;; number of pushes ... if odd we add "sub rsp" statements. Also, on such ;; systems, the call to fflush in _p_reg was crashing so it has been removed. ;; extern printf section .data __FORMAT_DBL: db "%1.20lf",0 __FORMAT_REG: db "%08x",0 __RAX: db "RAX",0 __RBX: db "RBX",0 __RCX: db "RCX",0 __RDX: db "RDX",0 __RBP: db "RBP",0 __RSI: db "RSI",0 __RDI: db "RDI",0 __RSP: db "RSP",0 __R8: db "R8 ",0 __R9: db "R9 ",0 __R10: db "R10",0 __R11: db "R11",0 __R12: db "R12",0 __R13: db "R13",0 __R14: db "R14",0 __R15: db "R15",0 __RIP: db "RIP",0 __RFLAGS: db "FLG",0 __SPACE: db " ",0 __SPACES: db " ",0 __NL: db 10,0 __COLON: db ": ",0 __XMMx: db "XMMx",0 section .bss __tmp: resd 1 __tmp2: resd 1 __temp_hex: resq 1 __temp_dbl: resq 1 section .text %macro _p_s 1 ; 1 here specifies we expect 1 argument push rdi ; save context push rsi push rax push rcx push rdx push r8 push r9 push r10 push r11 push r12 mov rdi,%1 ; %1 is the name of the first argument xor rax,rax ; clear rax call printf pop r12 ; restore context pop r11 pop r10 pop r9 pop r8 pop rdx pop rcx pop rax pop rsi pop rdi %endmacro ; _p_reg register ;------------------ ; Displays the contents of a 64-bit register in hexadecimal with the ; upper- and lower- 4-byte segments separated by a space. Any newlines ; needs to be added by the caller. ; ; We put the specified register into memory which allows us to see ; even registers that are used by C's printf. Also, printf treats ; parameters with "x" format string as 32-bit entities, so we ; have to call it twice with upper- and lower- segments of ; the register. ;----------------------------------------------------------- %macro _p_reg 1 push rdi ; save context push rsi push rax push rcx push rdx push r8 push r9 push r10 push r11 push r12 mov [__tmp],%1 ; put reg to display into tmp mov rdi,__FORMAT_REG mov rsi,[__tmp2] ; print upper 32 bits xor rax,rax call printf mov rdi,__SPACE ; print space xor rax,rax call printf mov rdi,__FORMAT_REG mov rsi,[__tmp] ; print lower 32 bits xor rax,rax call printf pop r12 pop r11 pop r10 pop r9 pop r8 pop rdx pop rcx pop rax pop rsi pop rdi %endmacro ; put_rflags ;------------- ; Displays the contents of the elusive rflags register. ; ; RFLAGS is modified by many instructions and so to get ; a snapshot we have to push its contents onto the stack ; prior to doing anything else. Then we pop its contents ; into a general purpose register to print it from there. ; After it's all said and done we need to restore its ; values and restore the temporary register as well. ;----------------------------------------------------------- %macro put_rflags 0 push r15 ; save r15 (temporary reg) pushfq ; pushfq to get rflags on stack pop r15 ; pop rflags off into r15 sub rsp,8 _p_s __RFLAGS ; modified by instructions, so ... _p_s __COLON _p_reg r15 ; display it _p_s __NL add rsp,8 push r15 ; push rflags value back on stack popfq ; pop it from stack into rflags pop r15 ; restore r15 to its orginal value %endmacro ; _p_dbl ;------------- ; Displays contents of the argument as a double-precision floating ; point value. ;----------------------------------------------------------- %macro _p_dbl 1 ; 1 here specifies we expect 1 argument push rdi ; save context push rsi push rax push rcx push rdx push r8 push r9 push r10 push r11 push r12 ; floating point values must be passed to printf in xmm0 sub rsp,16 movdqu [rsp],xmm0 mov rax, %1 movq xmm0, rax mov rdi,__FORMAT_DBL mov rax,1 call printf movdqu xmm0,[rsp] add rsp,16 pop r12 ; restore context pop r11 pop r10 pop r9 pop r8 pop rdx pop rcx pop rax pop rsi pop rdi %endmacro ; _p_fpu ;------------- ; Displays contents of the FPU registers ST0-ST7 ... as 64-bit values ;----------------------------------------------------------- %macro _p_xmm 1 push rax ; save context push rcx push rdx push rdi push rsi push r8 push r9 push r10 push r11 sub rsp,8 mov al,%1 add al,0x30 mov [__XMMx+3],al _p_s __XMMx _p_s __COLON _p_dbl [__temp_dbl] _p_s __SPACE _p_s __NL add rsp,8 pop r11 ; restore context pop r10 pop r9 pop r8 pop rsi pop rdi pop rdx pop rcx pop rax %endmacro ; dump_xmm ;------------- ; Displays contents of the XMM0-XMM7 registers (as doubles) ;----------------------------------------------------------- %macro dump_xmm 0 movq [__temp_dbl], xmm0 _p_xmm 0 movq [__temp_dbl], xmm1 _p_xmm 1 movq [__temp_dbl], xmm2 _p_xmm 2 movq [__temp_dbl], xmm3 _p_xmm 3 movq [__temp_dbl], xmm4 _p_xmm 4 movq [__temp_dbl], xmm5 _p_xmm 5 movq [__temp_dbl], xmm6 _p_xmm 6 movq [__temp_dbl], xmm7 _p_xmm 7 %endmacro ; dump_regs ;------------- ; Displays contents of all general purpose registers. ;----------------------------------------------------------- %macro dump_regs 0 _p_s __RAX _p_s __COLON _p_reg rax _p_s __SPACES _p_s __R8 _p_s __COLON _p_reg r8 _p_s __NL _p_s __RBX _p_s __COLON _p_reg rbx _p_s __SPACES _p_s __R9 _p_s __COLON _p_reg r9 _p_s __NL _p_s __RCX _p_s __COLON _p_reg rcx _p_s __SPACES _p_s __R10 _p_s __COLON _p_reg r10 _p_s __NL _p_s __RDX _p_s __COLON _p_reg rdx _p_s __SPACES _p_s __R11 _p_s __COLON _p_reg r11 _p_s __NL _p_s __RBP _p_s __COLON _p_reg rbp _p_s __SPACES _p_s __R12 _p_s __COLON _p_reg r12 _p_s __NL _p_s __RSI _p_s __COLON _p_reg rsi _p_s __SPACES _p_s __R13 _p_s __COLON _p_reg r13 _p_s __NL _p_s __RDI _p_s __COLON _p_reg rdi _p_s __SPACES _p_s __R14 _p_s __COLON _p_reg r14 _p_s __NL _p_s __RSP _p_s __COLON _p_reg rsp _p_s __SPACES _p_s __R15 _p_s __COLON _p_reg r15 _p_s __NL %endmacro