Fix disk/read write error handling and add int13h LBA BIOS extensions

.gitignore

@@ -2,5 +2,7 @@ bios.bin
 bios.lst
 tinyxms.sys
 tinyxms.lst
+quitemu.com
+quitemu.lst
 8086tiny
 hd.img

8086tiny.c

@@ -13,6 +13,7 @@
 #include <memory.h>
 #include <stdint.h>
 #include <stdlib.h>
+#include <errno.h>
 
 #define AMOUNT_XMS_HANDLES 32
 #define XMS_REPORTED_FREE (16 * 1024 * 1024)
@@ -64,6 +65,7 @@
 #ifndef GRAPHICS_UPDATE_DELAY
 #define GRAPHICS_UPDATE_DELAY 360000
 #endif
+#define APM_INST_DELAY 1000
 #define KEYBOARD_TIMER_UPDATE_DELAY 20000
 #define HALT_TIME_MICROSECONDS 100
 #define KEYBOARD_TIMER_DELAY_FROM_HALT 1000
@@ -204,11 +206,14 @@ unsigned char mem[RAM_SIZE + 16], io_ports[IO_PORT_COUNT + 16],
 	hlt_this_time, setting_ss, prior_setting_ss, reset_ip_after_rep_trace,
 	shift_count;
 unsigned short *regs16, reg_ip, seg_override, file_index, wave_counter, reg_ip_before_rep_trace;
-unsigned int op_source, op_dest, rm_addr, op_to_addr, op_from_addr, i_data0, i_data1, i_data2, scratch_uint, scratch2_uint, keyboard_timer_inst_counter, graphics_inst_counter, set_flags_type, GRAPHICS_X, GRAPHICS_Y, pixel_colors[16], vmem_ctr;
-int op_result, disk[3], scratch_int;
+unsigned int op_source, op_dest, rm_addr, op_to_addr, op_from_addr, i_data0, i_data1, i_data2, scratch_uint, scratch2_uint, keyboard_timer_inst_counter, graphics_inst_counter, apm_inst_counter, set_flags_type, GRAPHICS_X, GRAPHICS_Y, pixel_colors[16], vmem_ctr;
+int op_result, disk[3], scratch_int, device_status;
 time_t clock_buf;
 struct timeb ms_clock;
 
+#define DEVICE_STATUS_GRAPHICS 1
+#define DEVICE_STATUS_FASTCPU 2
+
 #ifndef NO_GRAPHICS
 SDL_AudioSpec sdl_audio = {44100, AUDIO_U8, 1, 0, 128};
 SDL_Surface *sdl_screen;
@@ -219,6 +224,7 @@ unsigned short vid_addr_lookup[VIDEO_RAM_SIZE], cga_colors[4] = {0 /* Black */,
 // Helper functions
 
 void callxms();
+void callapm();
 
 // Set carry flag
 char set_CF(int new_CF)
@@ -355,6 +361,38 @@ code_to_utf8(unsigned char *const buffer,
 	return 3;
 }
 
+// read/write routine -- Joshua Hudson <joshudson@gmail.com> 2023
+unsigned char readwrite(int handle, unsigned char *buffer, unsigned char nsectors, char mopcode)
+{
+	if (nsectors == 0) return 0xFF; // not sure if right, DosBOX does this
+	ssize_t r;
+	size_t len = (size_t)nsectors << 9;
+	ssize_t(*rw)(int,unsigned char*,size_t) = (mopcode != 3) ? (ssize_t(*)(int,unsigned char*,size_t))read:(ssize_t(*)(int,unsigned char*,size_t))write;
+	while (((r = rw(handle, buffer, len)) > 0 || r < 0 && errno == EINTR)) {
+		if (r < 0) continue; // EINTR
+		buffer += (size_t)r;
+		if (!(len -= (size_t)r)) {
+			// All data transferred
+			if (mopcode == 3) {
+#ifndef _WIN32
+				if (fdatasync(handle)) break; // r will not be 0; switches on errno
+//#else I'd have to rewrite a whole lot to implement the call on Windows.
+#endif
+			}
+			return 0;
+		}
+		// Network FS had to chunk write down
+	}
+	// Error pathway
+	if (r == 0) return 0x04; // Sector not found
+	switch (errno) {
+		case ENODEV: case ENXIO: return 0xAA; // Drive not ready
+		case EBADF: case EROFS: return mopcode == 3 ? 0x03 /* write protected */ : 0x0A;
+		case ENOSPC: case EDQUOT: return 0x04; // sparce file and out of disk: best fit is no such sector
+		default: return 0x0A; // bad sector: it's EIO and there aren't many likely cases
+	}
+}
+
 // Emulator entry point
 int main(int argc, char **argv)
 {
@@ -810,11 +848,13 @@ int main(int argc, char **argv)
 						CAST(short)mem[SEGREG(REG_ES, REG_BX, 36+)] = ms_clock.millitm;
 					OPCODE 2: // DISK_READ
 					OPCODE_CHAIN 3: // DISK_WRITE
-						regs8[REG_AL] = ~lseek(disk[regs8[REG_DL]], CAST(unsigned)regs16[REG_BP] << 9, 0)
-							? ((char)i_data0 == 3 ? (int(*)())write : (int(*)())read)(disk[regs8[REG_DL]], mem + SEGREG(REG_ES, REG_BX,), regs16[REG_AX])
-							: 0;
+						regs8[REG_AH] = ~lseek(disk[regs8[REG_DL]], CAST(unsigned)regs16[REG_BP] << 9, 0)
+							? readwrite(disk[regs8[REG_DL]], mem + SEGREG(REG_ES, REG_BX,), regs8[REG_AL], (char)i_data0)
+							: (errno == EINVAL) ? 0x04 /* out of range on disk device */ : 0xAA /* no disk */;
 					OPCODE 4:	// XMS
 						callxms();
+					OPCODE 5:
+						callapm();
 				}
 				if ((uint8_t)i_data0 == 11	// ud2
 					|| (uint8_t)i_data0 >= 32)
@@ -990,7 +1030,7 @@ int main(int argc, char **argv)
 			graphics_inst_counter = 0;
 			hlt_this_time = 0;
 			// Video card in graphics mode?
-			if (io_ports[0x3B8] & 2)
+			if (io_ports[0x3B8] & 2 && device_status & DEVICE_STATUS_GRAPHICS)
 			{
 				// If we don't already have an SDL window open, set it up and compute color and video memory translation tables
 				if (!sdl_screen)
@@ -1024,6 +1064,11 @@ int main(int argc, char **argv)
 			SDL_PumpEvents();
 		}
 #endif
+		if (!setting_ss && !hlt_this_time && !(device_status & DEVICE_STATUS_FASTCPU) && ++apm_inst_counter >= APM_INST_DELAY) {
+			hlt_this_time = 1;
+			apm_inst_counter = 0;
+		}
+
 		if (hlt_this_time) {
 			struct timespec ts;
 			ts.tv_sec = 0;
@@ -1055,7 +1100,8 @@ int main(int argc, char **argv)
 #ifndef NO_GRAPHICS
 	SDL_Quit();
 #endif
-	return 0;
+	// I really want to be able to pass an exit code out, but the pre-existing QUITEMU passes garbage. -JH
+	return (regs16[REG_BX] == 0x1234) ? regs8[REG_AL] : 0;
 }
 
 
@@ -1206,6 +1252,54 @@ uint32_t getfreexms() {
 	return lower;
 }
 
+void callapm() {
+	char buf[12];
+	int h, tmp;
+	switch (regs8[REG_AH]) {
+	OPCODE_CHAIN 0: // CPU slow
+		device_status &= ~DEVICE_STATUS_FASTCPU;
+	OPCODE 1: // CPU normal
+		device_status |= DEVICE_STATUS_FASTCPU;
+	OPCODE 2: // graphics card off
+		device_status &= ~DEVICE_STATUS_GRAPHICS;
+	OPCODE 3: // graphics card on
+		device_status |= DEVICE_STATUS_GRAPHICS;
+	OPCODE 4: // Get battery status
+#ifdef _WIN32
+		regs8[REG_BL] = 0xff;
+#else
+		h = open("/sys/class/power_supply/BAT0/status", O_RDONLY);
+		if (h >= 0 && (0 < read(h, buf, 12)))
+			regs8[REG_BL] = buf[0] == 'C' ? 3 /* charging */ : 2 /* critical */;
+		else
+			regs8[REG_BL] = 0xFF; // Unable
+		if (h >= 0) close(h);
+		h = open("/sys/class/power_supply/BAT0/capacity", O_RDONLY);
+		if (h >= 0 && ((tmp = read(h, buf, 10)) > 0))
+			buf[tmp] = 0, regs8[REG_CL] = atoi(buf);
+		else
+			regs8[REG_CL] = 0xFF; // Unable
+		if (h >= 0) close(h);
+		if (regs8[REG_CL] != 0xFF && regs8[REG_BL] == 2) {
+			if (regs8[REG_CL] >= 50) regs8[REG_BL] = 0; // High
+			else if (regs8[REG_CL] >= 10) regs8[REG_BL] = 1; // Low
+			// If we can't get battery charge and we're not charging it's critical
+		}
+#endif
+	OPCODE 5: // Get AC status
+#ifdef _WIN32
+		regs8[REG_BH] = 0xff;
+#else
+		h = open("/sys/class/power_supply/AC/online", O_RDONLY);
+		if (h >= 0 && (0 < read(h, buf, 2)))
+			regs8[REG_BH] = buf[0] - 1; // 0 = offline, 1 = online
+		else
+			regs8[REG_BH] = 0xFF; // Unable
+		if (h >= 0) close(h);
+#endif
+	}
+}
+
 
 void callxms() {
   uint32_t ii, free;

Makefile

@@ -18,11 +18,14 @@ bios.bin: bios.asm
 tinyxms.sys: tinyxms.asm
 	nasm -f bin -I ../lmacros/ -I lmacros/ -l tinyxms.lst -o tinyxms.sys tinyxms.asm
 
-8086tiny: 8086tiny.c bios.bin tinyxms.sys
+quitemu.com: quitemu.asm
+	nasm -f bin -o quitemu.com quitemu.asm
+
+8086tiny: 8086tiny.c bios.bin tinyxms.sys quitemu.com
 	${CC} 8086tiny.c ${OPTS_SDL} ${OPTS_ALL} -o 8086tiny
 	strip 8086tiny
 
-8086tiny_slowcpu: 8086tiny.c bios.bin tinyxms.sys
+8086tiny_slowcpu: 8086tiny.c bios.bin tinyxms.sys quitemu.com
 	${CC} 8086tiny.c ${OPTS_SDL} ${OPTS_ALL} ${OPTS_SLOWCPU} -o 8086tiny
 	strip 8086tiny
 
@@ -31,4 +34,4 @@ no_graphics: 8086tiny.c bios.bin tinyxms.sys
 	strip 8086tiny
 
 clean:
-	rm -f 8086tiny bios.bin bios.lst tinyxms.sys tinyxms.lst
+	rm -f 8086tiny bios.bin bios.lst tinyxms.sys tinyxms.lst quitemu.com