shithub: rgbds

Info  •  Files  •  Log  •  Branches

Output a non-empty RPN buffer from known expressions

The code expected to never get "known" expressions passed in, as RGBASM
otherwise patches the bytes in by itself; however, JR cannot be patched in
by RGBASM unless the section's base address is known as well!

--- a/src/asm/output.c

+++ b/src/asm/output.c

@@ -308,16 +308,16 @@

 				uint32_t ofs)

 {

 	struct Patch *pPatch = malloc(sizeof(struct Patch));

+	uint32_t rpnSize = expr->isKnown ? 5 : expr->nRPNPatchSize;

 	if (!pPatch)

 		fatalerror("No memory for patch: %s", strerror(errno));

-	pPatch->pRPN = malloc(sizeof(*pPatch->pRPN) * expr->nRPNPatchSize);

+	pPatch->pRPN = malloc(sizeof(*pPatch->pRPN) * rpnSize);

 	if (!pPatch->pRPN)

 		fatalerror("No memory for patch's RPN expression: %s",

 			   strerror(errno));

-	pPatch->nRPNSize = 0;

 	pPatch->nType = type;

 	fstk_DumpToStr(pPatch->tzFilename, sizeof(pPatch->tzFilename));

 	pPatch->nOffset = ofs;

@@ -324,8 +324,20 @@

 	pPatch->pcSection = sect_GetSymbolSection();

 	pPatch->pcOffset = curOffset;

-	writerpn(pPatch->pRPN, &pPatch->nRPNSize, expr->tRPN, expr->nRPNLength);

-	assert(pPatch->nRPNSize == expr->nRPNPatchSize);

+	/* If the expression's value is known, output a constant RPN expression directly */

+	if (expr->isKnown) {

+		pPatch->nRPNSize = rpnSize;

+		/* Make sure to update `rpnSize` above if modifying this! */

+		pPatch->pRPN[0] = RPN_CONST;

+		pPatch->pRPN[1] = (uint32_t)(expr->nVal) & 0xFF;

+		pPatch->pRPN[2] = (uint32_t)(expr->nVal) >> 8;

+		pPatch->pRPN[3] = (uint32_t)(expr->nVal) >> 16;

+		pPatch->pRPN[4] = (uint32_t)(expr->nVal) >> 24;

+	} else {

+		pPatch->nRPNSize = 0;

+		writerpn(pPatch->pRPN, &pPatch->nRPNSize, expr->tRPN, expr->nRPNLength);

+	}

+	assert(pPatch->nRPNSize == rpnSize);

 	return pPatch;

 }