From 7c24e9a9b02b04dcaf9507acb94091ea70a2c02d Mon Sep 17 00:00:00 2001
From: Xavi Del Campo <xavi.dcr@tutanota.com>
Date: Fri, 31 Jan 2020 10:32:23 +0100
Subject: Imported pristine psxsdk-20190410 from official repo

---
 libpsx/src/runexe/runexe.c | 76 ++++++++++++++++++++++++++++++++++++++++++++++
 libpsx/src/runexe/stage2.s | 40 ++++++++++++++++++++++++
 2 files changed, 116 insertions(+)
 create mode 100644 libpsx/src/runexe/runexe.c
 create mode 100644 libpsx/src/runexe/stage2.s

(limited to 'libpsx/src/runexe')

diff --git a/libpsx/src/runexe/runexe.c b/libpsx/src/runexe/runexe.c
new file mode 100644
index 0000000..5fe22b0
--- /dev/null
+++ b/libpsx/src/runexe/runexe.c
@@ -0,0 +1,76 @@
+/**
+ * PSXSDK
+ *
+ * RunEXE functionality
+ */
+
+#include <psx.h>
+#include <stdio.h>
+#include <string.h>
+#include <runexe.h>
+
+// Include runexe stage2 position independent code
+
+extern void PSX_RunExeStage2();
+extern void PSX_RunExeStage2_END();
+
+static void *runExeBuffer;
+
+int PSX_RunExe(void *exeBuffer)
+{
+	//unsigned char *exe = exeBuffer;
+	unsigned int *exe = exeBuffer;
+// Size of position indipendent code	
+	int sz = PSX_RunExeStage2_END -
+			PSX_RunExeStage2;
+	
+	if(!(PSX_GetInitFlags() & PSX_INIT_SAVESTATE))
+	{
+		printf("RunExe error: State was not saved!\n");
+		return 0;
+	}
+	
+	if(((unsigned int)exeBuffer & 3))
+	{
+		printf("RunExe: Alignment violation.\n");
+		printf("Specified buffer must have an address which is a multiplier of 4.\n");
+		return 0;
+	}
+	
+	// Check magic string
+	if(strcmp(exeBuffer, "PS-X EXE") != 0)
+		return 0; // Return failure if magic string couldn't be found
+	
+	runExeBuffer = exeBuffer;
+	
+	printf("PSXSDK RunExe Debug Information\n");
+	printf("t_addr = %08x\n", exe[6]);
+	printf("t_size = %08x\n", exe[7]);
+	printf("d_addr = %08x\n", exe[8]);
+	printf("d_size = %08x\n", exe[9]);
+	printf("b_addr = %08x\n", exe[10]);
+	printf("b_size = %08x\n", exe[11]);
+	printf("s_addr = %08x\n", exe[12]);
+	printf("s_size = %08x\n", exe[13]);
+	
+	printf("OK..! Farewell.\n");
+
+// Deinitialize the PSXSDK library	
+	PSX_DeInit();
+	
+// Copy the position independent stage2 code in high memory
+	memcpy((void*)0x801fef00, PSX_RunExeStage2, sz);
+	
+// Stack is unusable now! Do not do anything else except calling the stage2 code.
+	
+// Jump to the stage2 code without using the stack..
+	
+	__asm__("la $a0, runExeBuffer");
+	__asm__("nop");
+	__asm__("lw $a0, 0($a0)");
+	__asm__("j 0x801fef00");
+	__asm__("nop");
+	
+// This is never reached but keep the compiler happy	
+	return 0;
+}
diff --git a/libpsx/src/runexe/stage2.s b/libpsx/src/runexe/stage2.s
new file mode 100644
index 0000000..e60e109
--- /dev/null
+++ b/libpsx/src/runexe/stage2.s
@@ -0,0 +1,40 @@
+.global PSX_RunExeStage2
+.global PSX_RunExeStage2_END
+
+PSX_RunExeStage2:
+# a0 = address of PSX-EXE buffer
+
+# Load initial program counter in t0
+	lw $t0, 0x10($a0)
+# Load text section address in t1
+	lw $t1, 0x18($a0)
+# Load text section size in t2
+	lw $t2, 0x1c($a0)
+
+# Load initial sp register value in sp
+	lw $sp, 0x30($a0)
+
+# t3 = current source address
+	addiu $t3, $a0, 0x800
+
+# t4 = current destination address
+	addu $t4, $t1, $zero
+
+copyExeLoop:
+	beq $t2, $zero, copyExeLoop_End
+	nop
+copyExeLoop_2:
+	lb $t5, 0($t3)
+	nop
+	sb $t5, 0($t4)
+	addiu $t3, $t3, 1
+	addiu $t4, $t4, 1
+	addiu $t2, $t2, -1
+	beq $zero, $zero, copyExeLoop
+	
+copyExeLoop_End:
+# Jump to the program we loaded
+	jr $t0
+	nop
+
+PSX_RunExeStage2_END:
-- 
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