week5.md

push

push推入堆疊
--sp推入暫存器

c6虛擬機

指令   意義                                                    實作

LEA : load local address 載入區域變數                          a = (int)(bp + *pc++); 
IMM : load global address or immediate 載入全域變數或立即值     a = *pc++;
JMP : jump               躍躍指令                              pc = (int *)*pc;
JSR : jump to subroutine 跳到副程式                            *--sp = (int)(pc + 1); pc = (int *)*pc;
BZ  : branch if zero     if (a==0) goto m[pc]                 pc = a ? pc + 1 : (int *)*pc;
BNZ : branch if not zero if (a!=0) goto m[pc]                 pc = a ? (int *)*pc : pc + 1;
ENT : enter subroutine   進入副程式                            *--sp = (int)bp; bp = sp; sp = sp - *pc++;
ADJ : stack adjust       調整堆疊                              sp = sp + *pc++;
LEV : leave subroutine   離開副程式                            sp = bp; bp = (int *)*sp++; pc = (int *)*sp++;
LI  : load int           載入整數                              a = *(int *)a;
LC  : load char          載入字元                              a = *(char *)a;
SI  : store int          儲存整數                              *(int *)*sp++ = a;
SC  : store char         儲存字元                              a = *(char *)*sp++ = a;
PSH : push               推入堆疊                              *--sp = a;
OR  : a = a OR pop       pop 代表從堆疊中取出一個元素           a = *sp++ |  a;
XOR : a = a XOR pop                                           a = *sp++ ^  a;
AND : a = a AND pop                                           a = *sp++ &  a;
EQ : a = a EQ pop                                             a = *sp++ == a;
NE : a = a NE pop                                             a = *sp++ != a;
LT : a = a LT pop                                             a = *sp++ <  a;
GT : a = a GT pop                                             a = *sp++ >  a;
LE : a = a LE pop                                             a = *sp++ <= a;
GE : a = a GE pop                                             a = *sp++ >= a;
SHL : a = a SHL pop                                           a = *sp++ << a;
SHR : a = a SHR pop                                           a = *sp++ >> a;
ADD : a = a ADD pop                                           a = *sp++ +  a;
SUB : a = a SUB pop                                           a = *sp++ -  a;
MUL : a = a MUL pop                                           a = *sp++ *  a;
DIV : a = a DIV pop                                           a = *sp++ /  a;
MOD : a = a MOD pop                                           a = *sp++ %  a;
EXIT : 終止離開                                                return *sp;

指令   意義                              實作

OPEN: open                              a = open((char *)sp[1], *sp);
READ: read                              a = read(sp[2], (char *)sp[1], *sp);
CLOS: close                             a = close(*sp);
PRTF: printf                            t = sp + pc[1]; a = printf((char *)t[-1], t[-2], t[-3], t[-4], t[-5], t[-6]);
MALC: malloc                            a = (int)malloc(*sp);
FREE: free                              free((void *)*sp);
MSET: memset                            a = (int)memset((char *)sp[2], sp[1], *sp);
MCMP: memcmp                            a = memcmp((char *)sp[2], (char *)sp[1], *sp);