Imported pristine psxsdk-20190410 from official repo

1 files changed, 130 insertions, 0 deletions

diff --git a/tools/spasm/eval.c b/tools/spasm/eval.c
new file mode 100644
index 0000000..01f8f66
--- /dev/null
+++ b/tools/spasm/eval.c
@@ -0,0 +1,130 @@
+#include "spasm.h"
+
+/**
+ * Expressions in SPASM are implemented in a totally broken manner.
+ *
+ * The result of an expression is the value of its initial argument
+ * after executing the operation of the last operand with the last argument.
+ *
+ * For example dw $cafeba00+2+4 is not equal to dw $cafeba06
+ * but to dw $cafeba04.
+ * Likewise, dw $2+$cafeba00+4 is not equal to dw $cafeba06
+ * but to dw $6 !
+ */
+
+unsigned int spasm_eval(char *expr)
+{	
+	char *cset = "+-><&|*!";
+	char *csetp;
+	char *cp;
+	int ok;
+	int t = T_INTEGER;
+	char sbuf[128];
+	
+	if(strcmp(expr, "*") == 0) // Return current return address
+		return curPc;
+	
+	if(strcasecmp(curIns, "incbin") == 0)
+		return 0; // If current instruction is incbin, do not evaluate.
+		
+	if(*expr == '"' || *expr == '\'')
+		return 0; // I won't even try to evaluate strings!
+	
+	int ispan = strcspn(expr, cset);
+	
+	csetp = cset;
+
+	ok = 0; // ok will be 0 if we found no operator, 1 if we found it
+	
+	char op = '?';
+	
+	cp = NULL;
+	
+	while(*csetp)
+	{
+		char *tcp = strrchr(expr, *csetp);
+		
+		if(tcp) // Found operator
+		{
+			if(tcp > cp)
+				cp = tcp;
+			
+			if(*cp == '>')
+			{				
+				if(*(cp-1) != '>')
+					instruction_error("Bad operator");
+			}
+			
+			if(*cp == '<')
+			{
+				if(*(cp-1) != '<')
+					instruction_error("Bad operator");
+			}
+				
+			cp++;
+			ok = 1;
+			op = *csetp;
+			break;
+		}
+		
+		csetp++;
+	}
+	
+	unsigned int one = 0;
+	unsigned int two = 0;
+	
+	memcpy(sbuf, expr, ispan);
+	sbuf[ispan] = '\0';
+	
+	if(strlen(sbuf) == 0)
+		strcpy(sbuf, "0");
+		//instruction_error("Bad expression");
+	
+	//printf("sbuf = %s\n", sbuf);
+	one = asm_atoi(sbuf);
+	
+	t = atoiT[insArgc];
+	
+	if(ok)
+	{		
+		strcpy(sbuf, cp);
+		
+		if(strlen(sbuf) == 0)
+			instruction_error("Bad expression");
+		
+		two = asm_atoi(sbuf);
+		
+		if(t == T_INTEGER)
+			t = atoiT[insArgc];
+	}
+	
+	atoiT[insArgc] = t;
+	
+	switch(op)
+	{
+		case '+':
+			return one + two;
+		break;
+		case '-':
+			return one -  two;
+		break;
+		case '<':
+			return one << two;
+		break;
+		case '>':
+			return one >> two;
+		break;
+		case '&':
+			return one & two;
+		break;
+		case '|':
+		case '!':
+			return one | two;
+		break;
+		case '*':
+			return one * two;
+		break;
+	}
+	
+	return one;
+}