From 19f705076aec2c26bcc52a4e406f6886f0fc26f0 Mon Sep 17 00:00:00 2001
From: fincs <fincs.alt1@gmail.com>
Date: Mon, 15 Dec 2014 22:59:06 +0100
Subject: [PATCH] Add support for BREAKC/CALLC/IFC/JMPC

---
 Manual.md                    |   7 ++-
 source/picasso_assembler.cpp | 106 +++++++++++++++++++++++++++++++++++
 2 files changed, 111 insertions(+), 2 deletions(-)

diff --git a/Manual.md b/Manual.md
index 3021339..f00e76b 100644
--- a/Manual.md
+++ b/Manual.md
@@ -201,7 +201,7 @@ Syntax                            | Description
 - `bReg`: Represents a boolean uniform source operand.
 - `procName`: Represents the name of a procedure.
 - `labelName`: Represents the name of a label.
-- `opx` and `opy`: They represent a conditional operator that is applied to the source registers and whose result is stored in the appropriate flag (cmp.x and cmp.y respectively). Supported values include:
+- `opx` and `opy`: They represent a conditional operator that is applied to the source registers and whose result is stored in the appropriate flag (`cmp.x` and `cmp.y` respectively). Supported values include:
 	- `eq`: Equal
 	- `ne`: Not equal
 	- `lt`: Less than
@@ -209,4 +209,7 @@ Syntax                            | Description
 	- `gt`: Greater than
 	- `ge`: Greater or equal than
 	- `6` and `7`: currently unknown, supposedly the result they yield is always true.
-- `condExp`: Represents a conditional expression. Currently this is not implemented.
+- `condExp`: Represents a conditional expression, which uses the conditional flags `cmp.x` and `cmp.y` set by the CMP instruction. These flags may be negated using the `!` symbol, e.g. `!cmp.x`. The conditional expression can take any of the following forms:
+	- `flag1`: It tests a single flag.
+	- `flag1 && flag2`: It performs AND between the two flags. Optionally, a single `&` may be specified.
+	- `flag1 || flag2`: It performs OR between the two flags. Optionally, a single `|` may be specified.
diff --git a/source/picasso_assembler.cpp b/source/picasso_assembler.cpp
index 081a56d..1d1c8cc 100644
--- a/source/picasso_assembler.cpp
+++ b/source/picasso_assembler.cpp
@@ -590,6 +590,53 @@ static int parseReg(char* pos, int& outReg, int& outSw, int* idxType = NULL)
 	return 0;
 }
 
+static int parseCondExpOp(char* str, u32& outFlags, int& which)
+{
+	int negation = 0;
+	for (; *str == '!'; str++) negation ^= 1;
+	if (stricmp(str, "cmp.x")==0)
+	{
+		which = 1;
+		outFlags ^= negation<<25;
+		return 0;
+	}
+	if (stricmp(str, "cmp.y")==0)
+	{
+		which = 0;
+		outFlags ^= negation<<24;
+		return 0;
+	}
+	return throwError("invalid condition register: %s\n", str);
+}
+
+static int parseCondExp(char* str, u32& outFlags)
+{
+	outFlags = BIT(24) | BIT(25);
+	size_t len = strlen(str);
+	size_t pos = strcspn(str, "&|");
+	int op2 = -1;
+	if (pos < len)
+	{
+		char* str2 = str + pos;
+		int type = *str2;
+		*str2++ = 0;
+		if (*str2 == type)
+			str2++;
+		str = trim_whitespace(str);
+		str2 = trim_whitespace(str2);
+		if (type == '&')
+			outFlags |= 1<<22;
+		safe_call(parseCondExpOp(str2, outFlags, op2));
+	}
+	int op1 = -1;
+	safe_call(parseCondExpOp(str, outFlags, op1));
+	if (op1 == op2)
+		return throwError("condition register checked twice\n");
+	if (op2 < 0)
+		outFlags |= (op1+2)<<22;
+	return 0;
+}
+
 DEF_COMMAND(format0)
 {
 	ENSURE_NO_MORE_ARGS();
@@ -776,6 +823,64 @@ DEF_COMMAND(formatfor)
 
 DEF_COMMAND(format2)
 {
+	NEXT_ARG(condExp);
+
+	u32 instruction = 0;
+	safe_call(parseCondExp(condExp, instruction));
+
+	switch (opcode)
+	{
+		case MAESTRO_BREAKC:
+		{
+			ENSURE_NO_MORE_ARGS();
+
+#ifdef DEBUG
+			printf("%s:%02X %s\n", cmdName, opcode, condExp);
+#endif
+			break;
+		}
+
+		case MAESTRO_CALLC:
+		case MAESTRO_JMPC:
+		{
+			NEXT_ARG(targetName);
+			ENSURE_NO_MORE_ARGS();
+
+			ARG_TARGET(targetName);
+
+			Relocation r;
+			r.instPos = BUF.size();
+			r.target = targetName;
+			r.isProc = opcode==MAESTRO_CALLC;
+			g_relocs.push_back(r);
+
+#ifdef DEBUG
+			printf("%s:%02X %s, %s\n", cmdName, opcode, condExp, targetName);
+#endif
+			break;
+		}
+
+		case MAESTRO_IFC:
+		{
+			ENSURE_NO_MORE_ARGS();
+
+			if (NO_MORE_STACK)
+				return throwError("too many nested blocks\n");
+
+			StackEntry& elem = g_stack[g_stackPos++];
+			elem.type = SE_IF;
+			elem.pos = BUF.size();
+			elem.uExtra = 0;
+
+#ifdef DEBUG
+			printf("%s:%02X %s\n", cmdName, opcode, condExp);
+#endif
+			break;
+		}
+	}
+
+	BUF.push_back(FMT_OPCODE(opcode) | instruction);
+
 	return 0;
 }
 
@@ -865,6 +970,7 @@ static const cmdTableType cmdTable[] =
 
 	DEC_COMMAND(FOR, formatfor),
 
+	DEC_COMMAND(BREAKC, format2),
 	DEC_COMMAND(CALLC, format2),
 	DEC_COMMAND(IFC, format2),
 	DEC_COMMAND(JMPC, format2),